Two sets of arrows that exhibit the Müller-Lyer optical illusion. The set on the bottom shows that all the arrows are of the same length.

The Müller-Lyer illusion was first described by F.C. Müller-Lyer in 1889, and is one of the most famous size illusions. He found that two lines of the same length can be seen as longer or shorter by simply adding arrow heads that point in or out at either end.

In this study, Dr. Proulx and Green asked participants to search for a vertical line among distracting lines tilted to the left and right. All of the lines had arrow heads at either end that randomly pointed in or out, making some lines appear to be longer or shorter than others due to the illusion. They found that the line that appeared to be the longest captured the participants’ attention the most.

Two sets of arrows that exhibit the Müller-Lyer optical illusion. The set on the bottom shows that all the arrows are of the same length. (click to enlarge)

Reflexes are immediate and involuntary responses that allow a quick reaction, such as pulling your hand away from a hot surface.

Dr. Proulx adds: “If an illusion can capture attention in this way, then this suggests that the brain processes these visual clues rapidly and unconsciously. This also suggests that perhaps optical illusions represent what our brains like to see.”

The team hope that their findings can be used to help unlock clues about how the brain has evolved to not just represent the world as it is, but in a way that is most effective for survival.

“A number of conditions exhibit differences in attention, such as Autism and schizophrenia, and it would be useful to see whether visual illusions are still given priority even when other aspects of attention are affected,” adds Proulx.

Material adapted from Queen Mary, University of London.

The evidence suggests that for every gain in cognitive functions, for example better memory, increased attention or improved intelligence, there is a price to pay elsewhere – meaning a highly-evolved “supermind” is the stuff of science fiction.

University of Warwick psychology researcher Thomas Hills and Ralph Hertwig of the University of Basel looked at a range of studies, including research into the use of drugs like Ritalan which help with attention, studies of people with autism as well as a study of the Ashkenazi Jewish population.

For instance, among individuals with enhanced cognitive abilities – such as savants, people with photographic memories, and even genetically segregated populations of individuals with above average IQ, these individuals often suffer from related disorders, such as autism, debilitating synaesthesia and neural disorders linked with enhanced brain growth.

Similarly, drugs like Ritalan only help people with lower attention spans whereas people who do not have trouble focusing can actually perform worse when they take attention-enhancing drugs.

Dr. Hills said: “These kinds of studies suggest there is an upper limit to how much people can or should improve their mental functions like attention, memory or intelligence. Take a complex task like driving, where the mind needs to be dynamically focused, attending to the right things such as the road ahead and other road users – which are changing all the time. If you enhance your ability to focus too much, and end up over-focusing on specific details, like the driver trying to hide in your blind spot, then you may fail to see another driver suddenly veering into your lane from the other direction. Or if you drink coffee to make yourself more alert, the trade-off is that it is likely to increase your anxiety levels and lose your fine motor control. There are always trade-offs. In other words, there is a ‘sweet spot’ in terms of enhancing our mental abilities – if you go beyond that spot – just like in the fairy-tales – you have to pay the price.”

Material adapted from University of Warwick.

The research, entitled ‘Why Aren’t We Smarter Already: Evolutionary Trade-Offs and Cognitive Enhancements,’ is published in Current Directions in Psychological Science, a journal of the Association for Psychological Science.

Those with diets high in omega 3 fatty acids and in vitamins C, D, E and the B vitamins also had higher scores on mental thinking tests than people with diets low in those nutrients. These omega 3 fatty acids and vitamin D are primarily found in fish. The B vitamins and antioxidants C and E are primarily found in fruits and vegetables.

In another finding, the study showed that people with diets high in trans fats were more likely to have brain shrinkage and lower scores on the thinking and memory tests than people with diets low in trans fats. Trans fats are primarily found in packaged, fast, fried and frozen food, baked goods and margarine spreads.

The study involved 104 people with an average age of 87 and very few risk factors for memory and thinking problems. Blood tests were used to determine the levels of various nutrients present in the blood of each participant. All of the participants also took tests of their memory and thinking skills. A total of 42 of the participants had MRI scans to measure their brain volume.

Overall, the participants had good nutritional status, but seven percent were deficient in vitamin B12 and 25 percent were deficient in vitamin D.

Bowman said that the nutrient biomarkers in the blood accounted for a significant amount of the variation in both brain volume and thinking and memory scores. For the thinking and memory scores, the nutrient biomarkers accounted for 17 percent of the variation in the scores. Other factors such as age, number of years of education, and high blood pressure accounted for 46 percent of the variation. For brain volume, the nutrient biomarkers accounted for 37 percent of the variation.

“These results need to be confirmed, but obviously it is very exciting to think that people could potentially stop their brains from shrinking and keep them sharp by adjusting their diet,” Bowman said.

The study was the first to use nutrient biomarkers in the blood to analyze the effect of diet on memory and thinking skills and brain volume. Previous studies have looked at only one or a few nutrients at a time or have used questionnaires to assess people’s diet. But questionnaires rely on people’s memory of their diet, and they also do not account for how much of the nutrients are absorbed by the body, which can be an issue in the elderly.

The study was supported by the National Institutes of Health, the National Institute on Aging and National Center for Complementary and Alternative Medicine and the U.S. Department of Veteran Affairs, Portland VA Medical Center.

Material adapted from American Academy of Neurology (AAN).

“Many people think that it is just natural for older people’s brains to slow down as they age, but we’re finding that isn’t always true,” said Roger Ratcliff, professor of psychology at Ohio State University and co-author of the studies. “At least in some situations, 70-year-olds may have response times similar to those of 25-year olds.”

Ratcliff and his colleagues have been studying cognitive processes and aging in their lab for about a decade. In a new study published online this month in the journal Child Development, they extended their work to children.

Ratcliff said their results in children are what most scientists would have expected: very young children have slower response times and poorer accuracy compared to adults, and these improve as the children mature. But the more interesting finding is that older adults do not necessarily have slower brain processing than younger people, said Gail McKoon, professor of psychology at Ohio State and co-author of the studies.

“Older people don’t want to make any errors at all, and that causes them to slow down. We found that it is difficult to get them out of the habit, but they can with practice,” McKoon said.

Researchers uncovered this surprising finding by using a model developed by Ratcliff that considers both the reaction time and the accuracy shown by participants in speeded tasks. Most models only consider one of these variables.

“If you look at aging research, you find some studies that show older people are not impaired in accuracy, but other studies that show that older people do suffer when it comes to speed. What this model does is look at both together to reconcile the results,” Ratcliff said.

Ratcliff, McKoon and their colleagues have used several of the same experiments in children, young adults and the elderly.

In one experiment, participants are seated in front of a computer screen. Asterisks appear on the screen and the participants have to decide as quickly as possible whether there is a “small” number (31-50) or a “large” number (51-70) of asterisks. They press one of two keys on the keyboard, depending on their answer.

In another experiment, participants are again seated in front of a computer screen and are shown a string of letters. They have to decide whether those letters are a word in English or not. Some strings are easy (the nonwords are a random string of letters) and some are hard (the nonwords are pronounceable, such as “nerse”).

In the Child Development study, the researchers used the asterisk test on second and third graders, fourth and fifth graders, ninth and tenth graders, and college-aged adults. Third graders and college-aged adults participated in the word/nonword test.

The results showed that there was a rise in accuracy and decrease in response time on both tasks from the second and third-graders to the college-age adults.

The younger children took longer than older children and adults to respond in the experiment, Ratcliff said. They, like the elderly, were taking longer to make up their mind. But the younger children were also less accurate than younger adults in this study.

“Younger children are not able to make as good of use of the information they are presented, so they are less accurate,” Ratcliff said. “That improves as they mature.”

Older adults show a different pattern. In a study published in the journal Cognitive Psychology, Ratcliff and colleagues compared college-age subjects, older adults aged 60-74, and older adults aged 75-90. They used the same asterisk and word/nonword tests that were in the Child Development study. They found that there was little difference in accuracy among the groups, even the oldest of participants.

However, the college students had faster response times than did the 60-74 year olds, who were faster than the 75-90 year olds.

But the slower response times are not all the result of a decline in skills among older adults. In a previous study, the researchers encouraged older adults to go faster on these same tests. When they did, the difference in their response times compared to college-age students decreased significantly.

“For these simple tasks, decision-making speed and accuracy is intact even up to 85 and 90 years old,” McKoon said.

That doesn’t mean there are no effects of aging on decision-making speed and accuracy, Ratcliff said. In a study in the Journal of Experimental Psychology: General, Ratcliff, McKoon and another colleague found (like in studies from other laboratories) that accuracy for “associative memory” does decline as people age. For example, older people were much less likely to remember if they had studied a pair of words together than did younger adults.

But Ratcliff said that, overall, their research suggests there should be greater optimism about the cognitive skills of seniors.

“The older view was that all cognitive processes decline at the same rate as people age,” Ratcliff said.

“We’re finding that there isn’t such a uniform decline. There are some things that older people do nearly as well as young people.”

Ratcliff co-authored the Child Development paper with Jessica Love and John Opfer of Ohio State and Clarissa Thompson of the University of Oklahoma. Ratcliff and McKoon co-authored the Cognitive Psychology and Journal of Experimental Psychology: General papers with Anjali Thapar of Bryn Mawr College.

Some of the research was supported with grants from the National Institute on Aging and the National Institute of Mental Health.

Material adapted form Ohio State University.

“Patients with Parkinson disease (PD) are at an increased risk of developing dementia (PDD), with cumulative prevalence rates of up to 80 percent,” the authors write as background information in the article. “Approximately 25 percent of non-demented PD patients meet neuropsychological criteria for mild cognitive impairment (PD-MCI), which converts to PDD in many cases, and even mild cognitive deficits in PD are associated with functional impairments and worse quality of life.”

Researchers sought to assess the regions and patterns of brain atrophy in patients with PD with normal cognition (PD-NC), patients with PD with mild cognitive impairment (PD-MCI) and patients with PD with dementia-level cognitive deficits (PDD). Data were collected as part of the University of Pennsylvania Center of Excellence for Research on Neurodegenerative Diseases, and the study population included 84 patients with PD (61 PD-NC, 12 PD-MCI and 11 PDD) and 23 healthy control individuals, who all underwent magnetic resonance imaging (MRI) of the brain.

After controlling for other factors (such as patient age, sex and education level), the authors found no between-group differences in regional brain volumes for PD-NC patients compared with participants in the control group. Among patients with PD, there were cognitive group-level differences in hippocampal and medial temporal lobe volumes. Patients in the PD-MCI and PDD groups had smaller hippocampal volumes compared with PD-NC patients, but no differences were observed between patients in the PD-MCI and PDD groups. Patients in the PDD group, but not patients in the PD-MCI group, also had medial temporal lobe atrophy compared with patients in the PD-NC group. The authors found no between-group differences for other brain regions.

Patients in the PD-MCI group had a different pattern of brain atrophy compared to patients in the PD-NC group, but was similar to that of PDD patients. This pattern was characterized by atrophy in hippocampal volume, prefrontal cortex gray and white matter, occipital lobe gray and white matter, and parietal lobe white matter. In non-demented PD patients, the authors found a correlation between memory-encoding performance and hippocampal volume, “suggesting heterogeneity in the neural substrate of memory impairment.”

“With growing recognition of Parkinson disease with mild cognitive impairment as common and clinically significant, it will be important to develop consensus diagnostic criteria, validate assessment instruments for use in clinical care and research, and test treatments for their symptomatic and disease-modifying effects,” the authors conclude. “Use of a pattern classification approach may allow identification of diffuse regions of cortical gray and white matter atrophy early in the course of cognitive decline.”

Material adapted from JAMA.

Reference
Arch Neurol. 2011;[12]:1562-1568).

Instead, the Wisconsin researchers linked differences in math performance to social and cultural factors.

The new study, by Mertz and Jonathan Kane, a professor of mathematical and computer sciences at the University of Wisconsin-Whitewater, was published today (Dec. 12, 2011) in Notices of the American Mathematical Society. The study looked at data from 86 countries, which the authors used to test the “greater male variability hypothesis” famously expounded in 2005 by Lawrence Summers, then president of Harvard, as the primary reason for the scarcity of outstanding women mathematicians.

That hypothesis holds that males diverge more from the mean at both ends of the spectrum and, hence, are more represented in the highest-performing sector. But, using the international data, the Wisconsin authors observed that greater male variation in math achievement is not present in some countries, and is mostly due to boys with low scores in some other countries, indicating that it relates much more to culture than to biology.

The new study relied on data from the 2007 Trends in International Mathematics and Science Study and the 2009 Programme in International Student Assessment.

“People have looked at international data sets for many years”, Mertz says. “What has changed is that many more non-Western countries are now participating in these studies, enabling much better cross-cultural analysis.”

The Wisconsin study also debunked the idea proposed by Steven Levitt of “Freakonomics” fame that gender inequity does not hamper girls’ math performance in Muslim countries, where most students attend single-sex schools. Levitt claimed to have disproved a prior conclusion of others that gender inequity limits girls’ mathematics performance. He suggested, instead, that Muslim culture or single-sex classrooms benefit girls’ ability to learn mathematics.

By examining the data in detail, the Wisconsin authors noted other factors at work. “The girls living in some Middle Eastern countries, such as Bahrain and Oman, had, in fact, not scored very well, but their boys had scored even worse, a result found to be unrelated to either Muslim culture or schooling in single-gender classrooms,” says Kane.

He suggests that Bahraini boys may have low average math scores because some attend religious schools whose curricula include little mathematics. Also, some low-performing girls drop out of school, making the tested sample of eighth graders unrepresentative of the whole population.

“For these reasons, we believe it is much more reasonable to attribute differences in math performance primarily to country-specific social factors,” Kane says.

To measure the status of females relative to males within each country, the authors relied on a gender-gap index, which compares the genders in terms of income, education, health and political participation. Relating these indices to math scores, they concluded that math achievement at the low, average and high end for both boys and girls tends to be higher in countries where gender equity is better. In addition, in wealthier countries, women’s participation and salary in the paid labor force was the main factor linked to higher math scores for both genders.

“We found that boys — as well as girls — tend to do better in math when raised in countries where females have better equality, and that’s new and important,” says Kane. “It makes sense that when women are well-educated and earn a good income, the math scores of their children of both genders benefit.”

Mertz adds, “Many folks believe gender equity is a win-lose zero-sum game: If females are given more, males end up with less. Our results indicate that, at least for math achievement, gender equity is a win-win situation.”

U.S. students ranked only 31st on the 2009 Programme in International Student Assessment, below most Western and East-Asian countries. One proposed solution, creating single-sex classrooms, is not supported by the data. Instead, Mertz and Kane recommend increasing the number of math-certified teachers in middle and high schools, decreasing the number of children living in poverty and ensuring gender equality.

“These changes would help give all children an optimal chance to succeed,” says Mertz. “This is not a matter of biology: None of our findings suggest that an innate biological difference between the sexes is the primary reason for a gender gap in math performance at any level. Rather, these major international studies strongly suggest that the math-gender gap, where it occurs, is due to sociocultural factors that differ among countries, and that these factors can be changed.”

Material adapted from University of Wisconsin-Madison.

In the new study, Seeley, a professor of neurobiology and behavior, reports with five colleagues in the United States and the United Kingdom that scout bees also use inhibitory “stop signals” – a short buzz delivered with a head butt to the dancer – to inhibit the waggle dances produced by scouts advertising competing sites. The strength of the inhibition produced by each group of scouts is proportional to the group’s size. This inhibitory signaling helps ensure that only one of the sites is chosen. This is especially important for reaching a decision when two sites are equally good, Seeley said.

Previous research has shown that bees use stop signals to warn nest-mates about such dangers as attacks at a food source. However, this is the first study to show the use of stop signals in house-hunting decisions.

Such use of stop signals in decision making is “analogous to how the nervous system works in complex brains,” said Seeley. “The brain has similar cross inhibitory signaling between neurons in decision-making circuits.”

Co-authors Patrick Hogan and James Marshall of the University of Sheffield in the United Kingdom explored the implications of the bees’ cross-inhibitory signaling by modeling their collective decision-making process. Their analysis showed that stop signaling helps bees to break deadlocks between two equally good sites and to avoid costly dithering.

Material adapted from Cornell University.

“While we know babies born severely preterm generally achieve lower cognitive test scores, this is one of the first studies to look at how severely low birth weight impacts executive functioning, such as attention and visual memory, when these babies become young adults,” said study author professor Katri Räikkönen, PhD, of the University of Helsinki in Finland.

For the Helsinki Study of Very Low Birth Weight Adults, 103 adults born with a very low birth weight (less than 3.3 pounds) and 105 adults who weighed more than 3.3 pounds at the time of birth were given tests that measured their thinking skills, including vocabulary, ability to understand words, memory and IQ. Participants were between the ages of 21 and 30.

The study found that adults with very low birth weight scored lower or performed slower in general intelligence, executive functioning and attention and visual memory compared to the adults born at a low to normal weight. For example, those with a very low birth weight scored an average 8.4 points (0.57 standard deviation units) lower on the full IQ test and 0.30 – 0.54 standard deviation units lower on the executive functioning and attention and memory tests.

Researchers also found those with very low birth weight were more likely to have received remedial education while in school, but there were no differences in their self-reported academic performance.

“Interestingly, average school grades and the number of years of education completed were not affected by low birth weight in our study,” said Räikkönen. “However, our research underscores the importance of a baby’s full development in the womb.”

The study was supported by the Academy of Finland, University of Helsinki, the Finnish Medical Society Duodecim, Medical Society of Finland, the Finnish Foundation for Pediatric Research, the Finnish Special Governmental Subsidy for Health Sciences, the Jalmari and Rauha Ahokas Foundation, the Juho Vainio Foundation, the Emil Aaltonen Foundation, the Novo Nordisk Foundation, The Päivikki and Sakari Sohlberg Foundation, the Signe and Ane Gyllenberg Foundation, the Yrjö Jahnsson Foundation, the Orion-Pharma Foundation, the Sigrid Juselius Foundation, the Finnish National Graduate School of Clinical Investigation, the Wilhelm and Else Stockmann Foundation and the Pediatric Graduate School, University of Helsinki.

Material adapted from American Academy of Neurology (AAN).

“Understanding the interaction between exercise and a healthy diet could improve preventative and therapeutic measures against obesity by strengthening current approaches and treatments,” explains Miguel Alonso Alonso, researcher at Harvard University (USA) who has published a bibliographical compilation on the subject, to SINC.

The data from epidemiological studies suggest that tendencies towards a healthy diet and the right amount of physical exercise often come hand in hand. Furthermore, an increase in physical activity is usually linked to a parallel improvement in diet quality.

Exercise also brings benefits such as an increase in sensitivity to physiological signs of fullness. This not only means that appetite can be controlled better but it also modifies hedonic responses to food stimuli. Therefore, benefits can be classified as those that occur in the short term (of metabolic predominance) and those that are seen in the long term (of behavioral predominance).

According to Alonso Alonso, “physical exercise seems to encourage a healthy diet. In fact, when exercise is added to a weight-loss diet, treatment of obesity is more successful and the diet is adhered to in the long run.”

The authors of the study state how important it is for social policy to encourage and facilitate sport and physical exercise amongst the population. This should be present in both schools and our urban environment or daily lives through the use of public transport or availability of pedestrianised areas and sports facilities.

Exercise modifies the brain
Eating and physical activity are behaviors and are therefore influenced by cognitive processes that are a result of activity in different areas of the brain. Previous studies have already assessed changes in the brain and cognitive functions in relation to exercise: regular physical exercise causes changes in the working and structure of the brain.

The experts point out that these changes seem to have a certain specificity. The Harvard researcher supports the notion that “regular exercise improves output in tests that measure the state of the brain’s executive functions and increases the amount of grey matter and prefrontal connections.”

Inhibitory control is one of the executive functions of the brain and is basically the ability to suppress inadequate and non-conforming answers to an aim (the opposite of this would be impulsiveness), which makes modification or self-regulations of a behavior possible.

With regard to losing weight and sustaining weight loss in the long run, various recent studies suggest that executive functions such as inhibitory control and optimal functioning of the brain’s prefrontal areas could be the key to success. This success is mainly the fruit of a behavioral change. Inhibitory control could also help to prevent weight gain in healthy people.

The researcher outlines that “in time, exercise produces a potentiating effect of executive functions including the ability for inhibitory control, which can help us to resist the many temptations that we are faced with everyday in a society where food, especially hypercaloric food, is more and more omnipresent.”

Spain – Alarming Rise In Obesity
There has been an alarming rise in cases of obesity in Spain in recent years, so much so that prevalence in various areas of the country is higher than in many parts of the USA, which is traditionally thought of as the paradigm of obesity in the western world.

Furthermore, along with other Mediterranean countries, Spain has one of the highest rates of childhood obesity in Europe. The experts are urging society to become aware of the problem and join forces to prevent and treat all types of obesity.

Material adapted from Plataforma SINC.

Reference
R. J. Joseph, M. Alonso-Alonso, D. S. Bond, A. Pascual-Leone y G. L. Blackburn. “The neurocognitive connection between physical activity and eating behavior”. Obesity Reviews 12, 800–812; octubre de 2011.

What happens to this structure as we age? That was the question Timothy A. Salthouse, Brown-Forman professor of psychology at the University of Virginia, investigated in a new study appearing in an upcoming issue of Psychological Science, a journal published by the Association for Psychological Science. His findings advance psychologists’ understanding of the complexities of the aging brain.

“There are three hypotheses about how this works,” says Salthouse. “One is that abilities become more strongly integrated with one another as we age.” That theory suggests the general factor influences cognitive aging the most. The second — based on the idea that connectivity among different brain regions lessens with age — “is almost the opposite: that the changes in cognitive abilities become more rather than less independent with age.” The third was Salthouse’s hypothesis: The structure remains constant throughout the aging process.

Using a sample of 1,490 healthy adults ages 18 to 89, Salthouse performed analyses of the scores on 16 tests of five cognitive abilities — vocabulary, reasoning, spatial relations, memory, and perceptual speed. The primary analyses were on the changes in the test scores across an interval of about two and a half years.

The findings confirmed Salthouse’s hunch: “The effects of aging on memory, on reasoning, on spatial relations, and so on are not necessarily constant. But the structure within which these changes are occurring does not seem to change as a function of age.” In normal, healthy people, “the direction and magnitude of change may be different” when we’re 18 or 88, he says. “But it appears that the qualitative nature of cognitive change remains the same throughout adulthood.”

The study could inform other research investigating “what allows some people to age more gracefully than others,” says Salthouse. That is, do people who stay mentally sharper maintain their ability structures better than those who become more forgetful or less agile at reasoning? And in the future, applying what we know about the structures of change could enhance “interventions that we think will improve cognitive functioning” at any age or stage of life.

Material adapted from Association for Psychological Science.

Researcher Nathan Rose

But there is a catch – only if the information is unfamiliar. When presented with a face such as Hollywood celebrity Paris Hilton and asked to recognize the face a few seconds later, the woman could remember A-list party girl Hilton, but she was unable to remember novel, unfamiliar faces as well as healthy age, education and IQ matched control participants. Moreover, HC’s short-term memory was even impaired for faces that were famous, but whom HC did not know, such as former U.S. first lady Hillary Clinton.

The single case study with the woman was led by Baycrest’s Rotman Research Institute, in collaboration with the University of Toronto. The study is posted online in the science journal Neuropsychologia, ahead of print publication.

It is considered an important finding for understanding the nuanced workings of short-term memory in people with a devastating memory disorder such as amnesia. The study provides the first strong evidence that the short-term memory deficit in amnestic individuals is most apparent only when the individual is trying to recall new information that is “unfamiliar” to them. When information is already “familiar” from past repetitive exposure, it is more likely to be retained in short-term memory, also known as “working memory”.

Despite HC’s severe memory impairment – the result of experiencing hypoxia (loss of oxygen) in the first week of life – she is a relatively normal functioning individual and college graduate, who is an avid film buff and celebrity watcher.

“This woman is missing 50 percent of the normal volume of her hippocampus with no obvious damage to other parts of her brain. This provides an extraordinary opportunity to generate new insights about how this crucial memory center of the brain affects both short-term and long-term memory,” said lead investigator Nathan Rose, a post-doctoral fellow in Cognitive Neuroscience at Baycrest’s Rotman Research Institute.

“We wanted to test if HC’s short-term memory was impaired, and, if so, whether this impairment only existed for novel stimuli. That is exactly what we found.”

Amnestic individuals have profound deficits in long term memory and yet many seem to function fine by relying on their short-term memory which has traditionally been thought to be intact. However, a growing body of scientific evidence, including this latest study, is showing that “working memory” is also impaired in this population.

“Our findings add to the growing evidence that short-term memory is not intact in amnesia. However, to my knowledge, we are the first to directly test the hypothesis that short-term memory functions better if the information has some past familiarity to the person,” said Rotman scientist Dr. Fergus Craik, a collaborator on the study and co-editor of the Oxford Handbook of Memory.

That may explain why individuals with amnesia are often able to compensate for their profound memory deficit in social settings by seeking out familiar cues to support short-term memory.

Rose conducted the study with Dr. Craik and Dr. Shayna Rosenbaum, an associate scientist at Baycrest’s Rotman Research Institute and Associate Professor in the Department of Psychology at York University. Dr. Rosenbaum has previously studied HC and other unique cases of severe amnesia that have been a boon for scientific advancement in understanding human memory function.

Single cases with a clear pattern of specific brain deficits, such as HC, are incredibly rare and important for neuroscience. These cases enable researchers to generate more precise data that demonstrates a specific brain area is necessary for certain memory functions. Most individuals with amnesia typically present with diffuse damage in the brain which can complicate brain imaging and behavioral data interpretation.

The study In the study, HC and a control group of 20 undergraduate students participated in two experiments that tested their “working memory” – which is the ability to retain information (whether visual or verbal) for several seconds.

In the visuospatial experiment, participants were shown 40 famous faces and 40 non-famous faces and asked to recognize the faces after a short delay. HC had more difficulty than the control group in recalling non-famous faces (“unfamiliar” information) scoring 70% in accuracy compared to the control group’s 81%. However, HC’s recognition of famous faces (“familiar” information) was unimpaired relative to the controls; she scored 85% in accuracy – exactly the same as the control group. Drilling down, HC’s “working memory” performance was most robust (89% accuracy) for famous faces with which she was most familiar (for example, Paris Hilton).

In the second experiment, short lists of number sequences (like phone numbers) were visually presented to participants. They were to remember the correct sequences immediately afterward. HC could do this task perfectly fine, but when a distractor sentence had to be read aloud prior to the presentation of each digit, her performance was impaired compared to the controls.

A third memory test involved reading and then recalling familiar and less familiar words in the English lexicon (direction/common, fledgling/less common), as well as non-words (firpking). HC was also impaired (compared to controls) on the word task, but the impairment was larger for less familiar words and non-words. She performed almost as well as the healthy controls for familiar words.

For clinicians involved in cognitive rehabilitation, this latest evidence suggests that presenting information in a familiar context to individuals with amnesia may provide a significant benefit to their short-term memory function.

Material adapted from Baycrest Centre for Geriatric Care.

The study’s results are published in the scientific journal Biological Psychology.

“First-person shooter” games have been discussed in connection with violence over and over. Participants take on the role of a shooter fighting opponents in a war-like situation using different weapons. The Norwegian killer is said to have participated in such worlds intensely before he killed dozens of people in Oslo’s government district and on the vacation island of Utoya. And after the shooting sprees in Erfurt, Emsdetten and Winnenden, the debate whether violent games lower the inhibition threshold and result in violent behavior was revived again.

Psychologists, epileptologists and neurologists from the University of Bonn studied the effect of shoot ‘em up game images and other emotionally charged photos on the brain activity of heavy gamers. “Compared to people who abstain from first-person shooters, they show clear differences in how emotions are controlled,” reported lead author Dr. Christian Montag from the Institute of Psychology at the University of Bonn.

Excessive first-person shooting of about 15 hours a week
The 21 subjects ranging in age from 20 to 30 years played first-person shooters for about 15 hours per week on average. During this study, they were shown a standardized catalog of photos that reliably trigger emotions in human brains, using video glasses. At the same time, the researchers recorded the responses in their brains using one of the brain scanners at the Life & Brain Center of the University of Bonn. The images included photos as they are used in the violent games, but also shots of accident and disaster victims.

“This mix of images allowed us to transport the subjects both to the fictitious first-person shooter world they are familiar with and to also trigger emotions via real images,” explained Dr. Montag. This catalog of photos was also shown to a control group of 19 persons who had no experience with violent video games.

When the subjects regarded the real, negative pictures, there was greatly increased activity in their amygdalas. This region of the brain is strongly involved in processing negative emotions. “Surprisingly, the amygdalas in the subjects as well as in the control group were similarly stimulated,” reported Montag. “This shows that both groups responded to the photos with similarly strong emotions.” But the left medial frontal lobes were clearly less activated in the users of violent games than in the control subjects. This is the brain structure humans use to control their fear or aggression.

“First-person shooters do not respond as strongly to the real, negative image material because they are used to it from their daily computer activities,” Montag concluded. “One might also say that they are more desensitized than the control group.” On the other hand, while processing the computer game images, the first-person shooters showed higher activity in brain regions associated with memory recall and working memory than the control group members. “This indicates that the gamers put themselves into the video game due to the computer game images and were looking for a potential strategy to find a solution for the game status shown,” said Dr. Montag.

Violent games as a cause for changes in brain activity?
One question raised while interpreting the results is whether the users showed altered brain activity due to the games, or whether they were more tolerant of violence from the start and as a consequence, preferred first-person shooter games. The researchers from the University of Bonn were able to suggest an answer to this question based on the fact that they took into account various personality traits such as fearfulness, aggressiveness, callousness or emotional stability.

“There were no differences between the subjects and the control group in this area,” reported Dr. Montag. “This is an indication that the violent games are the cause of the difference in information processing in the brain.”

From the results, Dr. Montag has concluded that emotional desensitization does not only occur while playing computer games. “We were ultimately able to find the decreased control of emotions in first-person shooters for the real images, too,” he said. That is why he thinks these responses are not just limited to these virtual worlds. While there are many studies on video games and aggressive behavior, surprisingly few exist that look at their effect on the brain. “Our results provide indications that the extensive use of first-person shooters is not without its problems,” said Dr. Montag. “But we will need additional studies to shed some more light on the connections between violent games, brain activity, and actual behavior.”

Material adapted from University of Bonn.

Reference
Does excessive play of violent first-person-shooter-video-games dampen brain activity in response to emotional stimuli?, Biological Psychology, DOI:10.1016/j.biopsycho.2011.09.014

“The intricate interdependencies between BMI, SDB and cognition shown in our study are of particular importance in children, as their brains are still rapidly developing,” says study author Karen Spruyt, PhD, assistant professor in the Department of Pediatrics at the Pritzer School of Medicine. “Rising rates of obesity in children may amplify these relationships. Public health campaigns targeting obesity should emphasize not only the health benefits but the potential educational benefits of losing weight.”

According to Dr. Spruyt, “SDB amplified the risk of adverse cognitive and weight outcomes, while weight amplified the risk of SDB and adverse cognitive outcomes. Impaired cognitive functioning was associated with an increased risk of adverse weight outcomes and SDB.”

In contrast, she noted, “good cognitive abilities may be protective against increased body weight and SDB.”

The study enrolled 351 schoolchildren (mean age 7.9 years) in Louisville, Kentucky, who underwent neurocognitive testing with the Differential Abilities Scale following an overnight polysomnogram or sleep study. SDB was measured with the obstructive apnea/hypopnea index (AHI), defined as the number of apnea and hypopneas per hour of total sleep time. Anthropometric measurements included body mass index (BMI). Data were analyzed by Structural Equation Modeling, a statistical technique for testing and estimating causal relations between the variables of interest.

Models using “sleep-disordered breathing” revealed a substantive mediator role of SDB on the relationship between BMI and cognitive performance, with SDB increasing both adverse cognitive and adverse weight outcomes. In analyses using “weight,” BMI increased the risks of adverse SDB and cognitive outcomes. Finally, in models using “cognition” as the mediator, the poor ability to perform complex mental processing functions was shown to increase the risk of adverse weight and SDB outcomes.

“The mediator roles of weight and SDB were comparable, both adversely affecting cognitive functioning.” Dr. Spruyt noted. “Poorer integrative mental processing may also increase the risk of adverse health outcomes.”

The study had some limitations. The study included only normally developing children, limiting generalization of the results to more impaired populations. The authors also note that inclusion of children with more severe SDB might have altered the magnitude of the mediation effects.

“Along with campaigns targeting childhood obesity,” Dr. Spruyt adds, “screening for SDB in overweight children and children with learning difficulties may be justified based on our results.”

Material adapted from American Thoracic Society (ATS).

Download / Reference
SPRUYT, Karen & Gozal, David (2011). A Mediation Model Linking Body Weight, Cognition, And Sleep Disordered Breathing. American Journal of Respiratory and Critical Care Medicine.

Their article is entitled “Exercise Training Increases Mitochondrial Biogenesis in the Brain.” It appears in the Articles in Press section of the American Journal of Physiology – Regulatory, Integrative, and Comparative Physiology, published by the American Physiological Society.

Methodology
The researchers assigned mice to either an exercise group, which ran on an inclined treadmill six days a week for an hour, or to a sedentary group, which was exposed to the same sounds and handling as the exercise group but remained in their cages during the exercise period. After eight weeks, researchers examined brain and muscle tissue from some of the mice in each group to test for signs of increases in mitochondria. Additionally, some of the mice from each group performed a “run to fatigue” test to assess their endurance after the eight-week period.

Results
Confirming previous studies, the results showed that mice in the exercise group had increased mitochondria in their muscle tissue compared to mice in the sedentary group. However, the researchers also found that the exercising mice also showed several positive markers of mitochondria increase in the brain, including a rise in the expression of genes for proxisome proliferator-activated receptor coactivator 1-alpha, silent information regulator T1, and citrate synthase, all regulators for mitochondrial biogenesis; and mitochondrial DNA. These results correlate well with the animals’ increased fitness. Overall, mice in the exercise group increased their run to fatigue times from about 74 minutes to about 126 minutes. No change was seen for the sedentary mice.

Importance of the Findings
These findings suggest that exercise training increases the number of mitochondria in the brain much like it increases mitochondria in muscles. The study authors note that this increase in brain mitochondria may play a role in boosting exercise endurance by making the brain more resistant to fatigue, which can affect physical performance. They also suggest that this boost in brain mitochondria could have clinical implications for mental disorders, making exercise a potential treatment for psychiatric disorders, genetic disorders, and neurodegenerative diseases.

“These findings could lead to the enhancement of athletic performance through reduced mental and physical fatigue, as well as to the expanded use of exercise as a therapeutic option to attenuate the negative effects of aging, and the treatment and/or prevention of neurological diseases,” the authors say.

The study was conducted by Jennifer L. Steiner, E. Angela Murphy, Jamie L. McClellan, Martin D. Carmichael, and J. Mark Davis, all of the University of South Carolina.

Material adapted from American Physiological Society (APS).

“In babies born preterm, the more the cerebral cortex grows early in life the better children perform complex tasks when they reach six years old,” said study author A. David Edwards, DSc, of Imperial College in London. “The period before a full-term birth is critical for brain development. Problems occurring at this time have long-term consequences, and it appears that preterm birth affects brain growth.”

The study looked at brain growth rates of 82 infants who were born before 30 weeks gestational age using MRI scans of their brain between 24-44 weeks. Brain scans were collected repeatedly from immediately after the babies were born until their full-term due date. Their cognitive abilities were tested at two years old and again at six years old.

The study found that the faster the rate of cerebral cortex growth in infancy, the higher their scores were on the developmental and intelligence tests as children. A five to 10 percent reduction in the surface area of the cerebral cortex at full-term age predicted approximately one standard deviation lower score on the intelligence tests in later childhood. Motor skills were not correlated with the rate of cerebral cortex growth, and the overall brain size was not related to general cognitive ability.

“These findings show we should focus on the growth of specific regions of the brain like the cortex when trying to understand or diagnose potential problems in babies and fetuses,” said Edwards.

The study was supported by the Health Foundation, the Garfield Weston Foundation, Wellbeing of Women and the NIHR Imperial College Healthcare Comprehensive Biomedical Research Center.

Material adapted from American Academy of Neurology (AAN).

Understanding the neural basis of reinforcement and punishment processing is of paramount importance to cognitive neuroscience,” explains primary study author Dr. Timothy Vickery from the Department of Psychology at Yale University. “Most perceptual and cognitive functions are served by discrete brain structures, and thus the focus in the reward literature has been on understanding specialized circuits that process reward, such as the basal ganglia. In our study, we tested whether signals related to decision outcomes, encompassing both reinforcement and punishment, may be represented more extensively beyond the traditional reward- and penalty-processing areas that have been described.”

Dr. Vickery and colleagues imaged the brains of human subjects as they engaged in either matching-pennies or rock-paper-scissors games and used a sophisticated pattern analysis to analyze brain responses. The researchers were surprised to discover that both reinforcement and punishment representations were pervasive throughout the entire cortex. This suggests that reward and punishment may influence a much more widespread range of cognitive and perceptual processes than was previously imagined. Interestingly, the findings also indicated that the distribution of punishment signals and reinforcement signals are largely similar. This is in contrast to previous studies suggesting that there are limited regions encoding punishment and far more regions associated with reward.

Taken together, the findings provide evidence that both positive and negative outcomes can directly influence neural processing throughout the entire brain. “While it is likely that the basal ganglia and its projections are responsible for the core functions of reward-related processing, many other brain regions are at least provided with this information,” concludes Dr. Vickery. “This suggests an imperative to study the effects of reinforcement and punishment in domains where they are not usually considered as important factors—from low-level sensory systems to high-level social reasoning. Such distributed representations would have adaptive value for optimizing many types of cognitive processes and behavior in the natural world.”

Material adapted from Cell Press.

“Our findings show that these norms of fairness and altruism are more rapidly acquired than we thought,” said Jessica Sommerville, a University of Washington associate professor of psychology who led the study.

“These results also show a connection between fairness and altruism in infants, such that babies who were more sensitive to the fair distribution of food were also more likely to share their preferred toy,” she said.

The study has implications for nurturing human egalitarianism and cooperation. The journal PLoS ONE published the findings online Oct. 7, 2011. Co-author is Marco Schmidt, a doctoral student at the Max Planck Institute for Evolutionary Anthropology.

Previous studies reveal that 2-year-old children can help others – considered a measure of altruism – and that around age 6 or 7 they display a sense of fairness. Sommerville, an expert in early childhood development, suspected that these qualities could be apparent at even younger ages.

Babies around 15 months old begin to show cooperative behaviors, such as spontaneously helping others. “We suspected that fairness and altruism might also be apparent then, which could indicate the earliest emergence of fairness,” Sommerville said.

During the experiment, a 15-month old baby sat on his or her parent’s lap and watched two short videos of experimenters acting out a sharing task. In one video an experimenter holding a bowl of crackers distributed the food between two other experimenters. They did the food allocation twice, once with an equal allotment of crackers and the other with one recipient getting more crackers.

The second movie had the same plot, but the experimenters used a pitcher of milk instead of crackers.

Then the experimenters measured as the babies – 47 in all who were tested individually – looked at the food distributions. According to a phenomenon called “violation of expectancy,” babies pay more attention when they are surprised. Similarly, the researchers found that babies spent more time looking if one recipient got more food than the other.

“The infants expected an equal and fair distribution of food, and they were surprised to see one person given more crackers or milk than the other,” Sommerville said.

To see if the babies’ sense of fairness related to their own willingness to share, the researchers did a second task in which a baby could choose between two toys: a simple LEGO block or a more elaborate LEGO doll. Whichever toy the babies chose, the researchers labeled as the infant’s preferred toy.

Then an experimenter who the babies had not seen before gestured toward the toys and asked, “Can I have one?” In response, one third of the infants shared their preferred toy and another third shared their non-preferred toy. The other third of infants did not share either toy, which might be because they were nervous around a stranger or were unmotivated to share.

“The results of the sharing experiment show that early in life there are individual differences in altruism,” Sommerville said.

Comparing the toy-sharing task and the food-distribution task results, the researchers found that 92 percent of the babies who shared their preferred toy – called “altruistic sharers” – spent more time looking at the unequal distributions of food. In contrast, 86 percent of the babies who shared their less-preferred toy, the “selfish sharers,” were more surprised, and paid more attention, when there was a fair division of food.

“The altruistic sharers were really sensitive to the violation of fairness in the food task,” Sommerville said. Meanwhile, the selfish sharers showed an almost opposite effect, she said.

Does this mean that fairness and altruism are due to nature, or can these qualities be nurtured? Sommerville’s research team is investigating this question now, looking at how parents’ values and beliefs alter an infant’s development.

“It’s likely that infants pick up on these norms in a nonverbal way, by observing how people treat each other,” Sommerville said.

Material adapted from University of Washington.

The study, which will be published in the November 2011 issue of Pediatrics (published online Oct. 3), was conducted with existing data of 5,357 children from the Rochester Epidemiology Project and examined the medical and educational records of 1,050 children born between 1976 and 1982 in a single school district in Rochester.

“After removing factors related to existing health issues, we found that children exposed more than once to anesthesia and surgery prior to age 2 were approximately three times as likely to develop problems related to speech and language when compared to children who never underwent surgeries at that young age,” says David Warner, M.D., Mayo Clinic anesthesiologist and co-author of the study.

Among the 5,357 children in the cohort, 350 underwent surgeries with general anesthesia before their second birthday and were matched with 700 children who did not undergo a procedure with anesthesia. Of those exposed to anesthesia, 286 experienced only one surgery and 64 had more than one. Among those children who had multiple surgeries before age 2, 36.6 percent developed a learning disability later in life. Of those with just one surgery, 23.6 percent developed a learning disability, which compares to 21.2 percent of the children who developed learning disabilities but never had surgery or anesthesia before age 2. However, researchers saw no increase in behavior disorders among children with multiple surgeries.

“Our advice to parents considering surgery for a child under age 2 is to speak with your child’s physician,” says Randall Flick, M.D., Mayo Clinic pediatric anesthesiologist and lead author of the study. “In general, this study should not alter decision-making related to surgery in young children. We do not yet have sufficient information to prompt a change in practice and want to avoid problems that may occur as a result of delaying needed procedures. For example, delaying ear surgery for children with repeated ear infections might cause hearing problems that could create learning difficulties later in school.”

This study, funded by the U.S. Food and Drug Administration, examines the same population data used in a 2009 study by Mayo Clinic researchers, which reviewed records for children under age 4 and was published in the medical journalAnesthesiology.

The 2009 Mayo Clinic study was the first complete study in humans to suggest that exposure of children to anesthesia might affect development of the brain. Several previous studies suggested that anesthetic drugs might cause abnormalities in the brains of young animals. The study released today is significant because it examines children experiencing anesthesia and surgeries under age 2 and removes factors associated with existing health issues.

Additional co-authors include Slavica Katusic, M.D.; Robert Colligan, Ph.D.; Robert Wilder, M.D., Ph.D.; Michael Olson, Juraj Sprung, M.D., Ph.D.; Amy Weaver; and Darrell Schroeder; all of Mayo Clinic, and Robert Voigt, M.D., Texas Children’s Hospital.

Material adapted from Mayo Clinic.

As yet, the technology can only reconstruct movie clips people have already viewed. However, the breakthrough paves the way for reproducing the movies inside our heads that no one else sees, such as dreams and memories, according to researchers.

“This is a major leap toward reconstructing internal imagery,” said Professor Jack Gallant, a UC Berkeley neuroscientist and coauthor of the study to be published online Sept. 22 in the journal Current Biology. “We are opening a window into the movies in our minds.”

Eventually, practical applications of the technology could include a better understanding of what goes on in the minds of people who cannot communicate verbally, such as stroke victims, coma patients and people with neurodegenerative diseases.

It may also lay the groundwork for brain-machine interface so that people with cerebral palsy or paralysis, for example, can guide computers with their minds.

However, researchers point out that the technology is decades from allowing users to read others’ thoughts and intentions, as portrayed in such sci-fi classics as “Brainstorm,” in which scientists recorded a person’s sensations so that others could experience them.

Previously, Gallant and fellow researchers recorded brain activity in the visual cortex while a subject viewed black-and-white photographs. They then built a computational model that enabled them to predict with overwhelming accuracy which picture the subject was looking at.

In their latest experiment, researchers say they have solved a much more difficult problem by actually decoding brain signals generated by moving pictures.

“Our natural visual experience is like watching a movie,” said Shinji Nishimoto, lead author of the study and a post-doctoral researcher in Gallant’s lab. “In order for this technology to have wide applicability, we must understand how the brain processes these dynamic visual experiences.”

Nishimoto and two other research team members served as subjects for the experiment, because the procedure requires volunteers to remain still inside the MRI scanner for hours at a time.

They watched two separate sets of Hollywood movie trailers, while fMRI was used to measure blood flow through the visual cortex, the part of the brain that processes visual information. On the computer, the brain was divided into small, three-dimensional cubes known as volumetric pixels, or “voxels.”

“We built a model for each voxel that describes how shape and motion information in the movie is mapped into brain activity,” Nishimoto said.

The brain activity recorded while subjects viewed the first set of clips was fed into a computer program that learned, second by second, to associate visual patterns in the movie with the corresponding brain activity.

Brain activity evoked by the second set of clips was used to test the movie reconstruction algorithm. This was done by feeding 18 million seconds of random YouTube videos into the computer program so that it could predict the brain activity that each film clip would most likely evoke in each subject.

Finally, the 100 clips that the computer program decided were most similar to the clip that the subject had probably seen were merged to produce a blurry yet continuous reconstruction of the original movie.

Reconstructing movies using brain scans has been challenging because the blood flow signals measured using fMRI change much more slowly than the neural signals that encode dynamic information in movies, researchers said. For this reason, most previous attempts to decode brain activity have focused on static images.

“We addressed this problem by developing a two-stage model that separately describes the underlying neural population and blood flow signals,” Nishimoto said.

Ultimately, Nishimoto said, scientists need to understand how the brain processes dynamic visual events that we experience in everyday life.

“We need to know how the brain works in naturalistic conditions,” he said. “For that, we need to first understand how the brain works while we are watching movies.”

Material adapted from University of California – Berkeley.

Lebel recently moved to the United States to work at UCLA, where she is a post-doctoral fellow working with an expert in brain-imaging research. “This is the first long-range study, using a type of imaging that looks at brain wiring, to show that in the white matter there are still structural changes happening during young adulthood,” says Lebel. “The white matter is the wiring of the brain; it connects different regions to facilitate cognitive abilities. So the connections are strengthening as we age in young adulthood.”

The duo recently published their findings in the Journal of Neuroscience. For their research they used magnetic resonance imaging or MRIs to scan the brains of 103 healthy people between the ages of five and 32. Each study subject was scanned at least twice, with a total of 221 scans being conducted overall. The study demonstrated that parts of the brain continue to develop post-adolescence within individual subjects.

The research results revealed that young adult brains were continuing to develop wiring to the frontal lobe; tracts responsible for complex cognitive tasks such as inhibition, high-level functioning and attention. The researchers speculated in their article that this may be due to a plethora of life experiences in young adulthood such as pursing post-secondary education, starting a career, independence and developing new social and family relationships.

An important observation the researchers made when reviewing the brain-imaging scan results was that in some people, several tracts showed reductions in white matter integrity over time, which is associated with the brain degrading. The researchers speculated in their article that this observation needs to be further studied because it may provide a better understanding of the relationship between psychiatric disorders and brain structure. These disorders typically develop in adolescence or young adulthood.

“What’s interesting is a lot of psychiatric illness and other disorders emerge during adolescence, so some of the thought might be if certain tracts start to degenerate too soon, it may not be responsible for these disorders, but it may be one of the factors that makes someone more susceptible to developing these disorders,” says Beaulieu.

“It’s nice to provide insight into what the brain is doing in a healthy control population and then use that as a springboard so others can ask questions about how different clinical disorders like psychiatric disease and neurological disease may be linked to brain structure as the brain progresses with age.”

Material adapted from University of Alberta Faculty of Medicine & Dentistry.

Researchers Palmeri, Logan and Schall

Impulse control is an important aspect of the brain’s executive functions – the procedures that it uses to control its own activity. Problems with impulse control are involved in ADHD and a number of other psychiatric disorders including schizophrenia. The current research set out to better understand how the brain is wired to control impulsive behavior.

“Our study was focused on the control of eye movements, but we think it is widely applicable,” said Vanderbilt Ingram Professor of Neuroscience Jeffrey Schall, co-author of the new study.

Schall directed the study with Vanderbilt Centennial Professor of Psychology Gordon Logan and Associate Professor of Psychology Thomas Palmeri in collaboration with Pierre Pouget from the French National Institute of Health and Medical Research (INSERM), Leanne Boucher, assistant professor of psychology at Nova Southeastern University, and Martin Paré from Queen’s University in Ontario, Canada.

Understanding impulse control
There are two sets of neurons that control how we process and react to what we see, hear, smell, taste or touch. The first set, sensory neurons, respond to different types of stimuli in the environment. They are connected to movement neurons that trigger an action when the information they receive from the sensory neurons reaches a certain threshold. Response time to stimuli varies considerably depending on a number of factors. When accuracy is important, for example, response times lengthen. When speed is important, response times shorten.

According to Logan, there is clear evidence of a link between reaction time variations and certain mental disorders. “In countermanding tests, the response times of people with ADHD don’t slow down as much following a stop-signal trial as normal subjects, while response times of schizophrenics tend to be much slower than normal,” he said.

Since the 1970′s, researchers have believed that the brain controls these response times by altering the threshold at which the movement neurons trigger an action: When rapid action is preferable, the threshold is lowered and when greater deliberation is called for, the threshold is increased.

In a direct test of this theory, however, Logan, Palmeri, Schall and their collaborators found that differences in when the movement neurons began accumulating information from the sensory neurons – rather than differences in the threshold – appear to explain the adjustment in response times.

This discovery forced them to make major modifications in the existing cognitive model of impulse control and is an example of the growing usefulness of such models to understand in much greater detail what is occurring in the brain to cause both normal and abnormal behaviors.

“Psychopathologists are beginning to use these models to make connections with various brain disorders that we haven’t been able to make before,” Palmeri said.

In the experiment
The researchers directly tested the threshold hypothesis by analyzing recordings of neuronal activity in macaque monkeys performing a visual eye movement stopping task. In this task, the monkey is trained to look directly at a target that is flashed in different locations on a computer screen, except when the target is quickly followed by a stop signal. When this happens, the monkey gets a reward if it continues to look at the fixation spot in the center of the screen.

In the experiment, the delay between the appearance of the target and stop signals ranged from 25 milliseconds to 275 milliseconds. During this time, the movement neurons are still processing the signals generated by the appearance of the target. The longer the delay, the more difficult it is for the monkey to keep from glancing at the target. In both humans and monkeys, the reaction time in these tasks is significantly longer immediately following the stop signal.

The researchers believe their discovery is significant because it sheds new light on how the brain controls all sorts of basic impulses. It is possible that neurons from the medial frontal cortex, which performs executive control of decision-making, in the parietal lobe, which determines our spatial sense, or the temporal lobe, which plays a role in memory formation, may affect impulse control by altering the onset delay time of neurons involved in a number of other basic stimulus/response reactions.

Material adapted from Vanderbilt University.

Scientists have long known that functional specificity exists in certain domains: In the motor system, for example, there is one patch of neurons that controls the fingers of your left hand, and another that controls your tongue. But what about more complex functions such as recognizing faces, using language or doing math? Are there special brain regions for those activities, or do they use general-purpose areas that serve whatever task is at hand?

The researchers use an innovative method to analyze fMRI data subject by subject, allowing them to discern individual patterns of brain activity. Photo: Patrick Gillooly

But according to Fedorenko and her co-authors — Nancy Kanwisher, the Walter A. Rosenblith Professor of Cognitive Neuroscience, and undergraduate student Michael Behr — this apparent overlap may simply be due to flaws in methodology, i.e., how fMRI data is traditionally gathered and analyzed. In their new study, published in this week’s Proceedings of the National Academy of Sciences, they used an innovative technique they have been developing over the past few years; the new method yielded evidence that there are, in fact, bits of the brain that do language and nothing else.

Forget the forest, it is all in the trees
fMRI studies of language are typically done by group analysis, meaning that researchers test 10, 20 or even 50 subjects, then average data together onto a common brain space to search for regions that are active across brains.

But Fedorenko says this is not an ideal way to do things, mainly because the fine-grained anatomical differences between brains can cause data “smearing,” making it look as if one region is active in two different tasks when in reality, the tasks activate two neighboring — but not overlapping — regions in each individual subject.

A map of the different brain areas that are active while a subject performs a language task (red) and a cognitive control task (blue), showing that nearby but distinct regions are used for each activity. Image courtesy of Fedorenko et al. (click to enlarge)

It is the same way for brains. “Brains are different in their folding patterns, and where exactly the different functional areas fall relative to these patterns,” Fedorenko says. “The general layout is similar, but there isn’t fine-grained matching.” So, she says, analyzing data by “aligning brains in some common space … is just never going to be quite right.”

Ideally, then, data would be analyzed for each subject individually; that is, patterns of activity in one brain would only ever be compared to patterns of activity from that same brain. To do this, the researchers spend the first 10 to 15 minutes of each fMRI scan having their subject do a fairly sophisticated language task while tracking brain activity. This way, they establish where the language areas lie in that individual subject, so that later, when the subject performs other cognitive tasks, they can compare those activation patterns to the ones elicited by language.

From left, MIT undergraduate Michael Behr, principal investigator Nancy Kanwisher and research scientist Evelina Fedorenko in front of the fMRI machine they use to measure real-time brain activity associated with language and other cognitive tasks. Photo: Patrick Gillooly

Out of the nine regions they analyzed — four in the left frontal lobe, including the region known as Broca’s area, and five further back in the left hemisphere — eight uniquely supported language, showing no significant activation for any of the seven other tasks. These findings indicate a “striking degree of functional specificity for language,” as the researchers report in their paper.

Future studies will test the newly identified language areas with even more non-language tasks to see if their functional specificity holds up; the researchers also plan to delve deeper into these areas to discover which particular linguistic jobs each is responsible for.

Fedorenko says the results do not imply that every cognitive function has its own dedicated piece of cortex; after all, we are able to learn new skills, so there must be some parts of the brain that are both high-level and functionally flexible. Still, she says, the results give hope to researchers looking to draw some distinctions within in the human cortex: “Brain regions that do related things may be nearby … [but] it’s not just all one big mushy multifunctional thing in there.”

Material adapted from Massachusetts Institute of Technology.

U.Va. psychologists tested 4-year-old children immediately after they had watched nine minutes of the popular show “SpongeBob SquarePants” and found that their executive function – the ability to pay attention, solve problems and moderate behavior – had been severely compromised when compared to 4-year-olds who had either watched nine minutes of “Caillou,” a slower-paced, realistic public television show, or had spent nine minutes drawing.

“There was little difference on the tests between the drawing group and the group that watched ‘Caillou,’” said lead investigator Angeline Lillard, a psychology professor in U.Va.’s College of Arts & Sciences.

Lillard said there may be two reasons that a fast-paced and fantastical show would have a negative effect on the learning and behavior of young children.

“It is possible that the fast pacing, where characters are constantly in motion from one thing to the next, and extreme fantasy, where the characters do things that make no sense in the real world, may disrupt the child’s ability to concentrate immediately afterward,” she said. “Another possibility is that children identify with unfocused and frenetic characters, and then adopt their characteristics.”

The children in the study, whether they watched the television shows or drew, were tested immediately afterward for how well they solved problems and followed rules, remembered what they had been told, and were able to delay gratification.

Lillard advises parents to consider the findings when making decisions as to which television shows to allow their young children to watch – if they watch television at all.

“Parents should know that children who have just watched ‘SpongeBob Squarepants,’ or shows like it, might become compromised in their ability to learn and behave with self-control,” she said.

Lillard and her co-author, graduate student Jennifer Peterson, said that 4-year-olds are in an important development stage of their lives and that what they watch on television may have lasting effects on their lifelong learning and behaviors. Their study, however, focused on the immediate effects.

“Young children are beginning to learn how to behave as well as how to learn,” Lillard said. “At school, they have to behave properly, they need to sit at a table and eat properly, they need to be respectful, and all of that requires executive functions. If a child has just watched a television show that has handicapped these abilities, we cannot expect the child to behave at their normal level in everyday situations.”

She recommends that parents use creative learning activities, such as drawing, using building blocks and board games, and playing outdoors to help their children develop sound behaviors and learning skills.

“Executive function is extremely important to children’s success in school and in everyday life,” Lillard said. “It’s important to their psychological and physical well-being.”

Material adapted from University of Virginia.

The researchers report in the journal Frontiers in Human Neuroscience that they used functional magnetic resonance imaging (fMRI) to identify areas of the brain activated when study participants thought about physical objects such as a carrot, a horse or a house. The researchers then generated a list of topics related to those objects and used the fMRI images to determine the brain activity that words within each topic shared. For instance, thoughts about “eye” and “foot” produced similar neural stirrings as other words related to body parts.

Once the researchers knew the brain activity a topic sparked, they were able to use fMRI images alone to predict the subjects and words a person likely thought about during the scan. This capability to put people’s brain activity into words provides an initial step toward further exploring themes the human brain touches upon during complex thought.

“The basic idea is that whatever subject matter is on someone’s mind — not just topics or concepts, but also, emotions, plans or socially oriented thoughts — is ultimately reflected in the pattern of activity across all areas of his or her brain,” said the team’s senior researcher, Matthew Botvinick, an associate professor in Princeton’s Department of Psychology and in the Princeton Neuroscience Institute.

“The long-term goal is to translate that brain-activity pattern into the words that likely describe the original mental ‘subject matter,’” Botvinick said. “One can imagine doing this with any mental content that can be verbalized, not only about objects, but also about people, actions and abstract concepts and relationships. This study is a first step toward that more general goal.

“If we give way to unbridled speculation, one can imagine years from now being able to ‘translate’ brain activity into written output for people who are unable to communicate otherwise, which is an exciting thing to consider. In the short term, our technique could be used to learn more about the way that concepts are represented at the neural level — how ideas relate to one another and how they are engaged or activated.”

The research, which was published Aug. 23, was funded by a grant from the National Institute of Neurological Disease and Stroke, part of the National Institutes of Health.

Depicting a person’s thoughts through text is a “promising and innovative method” that the Princeton project introduces to the larger goal of correlating brain activity with mental content, said Marcel Just, a professor of psychology at Carnegie Mellon University. The Princeton researchers worked from brain scans Just had previously collected in his lab, but he had no active role in the project.

“The general goal for the future is to understand the neural coding of any thought and any combination of concepts,” Just said. “The significance of this work is that it points to a method for interpreting brain activation patterns that correspond to complex thoughts.”

Tracking the brain’s ‘semantic threads’
Largely designed and conducted in Botvinick’s lab by lead author and Princeton postdoctoral researcher Francisco Pereira, the study takes a currently popular approach to neuroscience research in a new direction, Botvinick said. He, Pereira and coauthor Greg Detre, who earned his Ph.D. from Princeton in 2010, based their work on various research endeavors during the past decade that used brain-activity patterns captured by fMRI to reconstruct pictures that participants viewed during the scan.

“This ‘generative’ approach — actually synthesizing something, an artifact, from the brain-imaging data — is what inspired us in our study, but we generated words rather than pictures,” Botvinick said.

“The thought is that there are many things that can be expressed with language that are more difficult to capture in a picture. Our study dealt with concrete objects, things that are easy to put into a picture, but even then there was an interesting difference between generating a picture of a chair and generating a list of words that a person associates with ‘chair.’”

Those word associations, lead author Pereira explained, can be thought of as “semantic threads” that can lead people to think of objects and concepts far from the original subject matter yet strangely related.

“Someone will start thinking of a chair and their mind wanders to the chair of a corporation then to Chairman Mao — you’d be surprised,” Pereira said. “The brain tends to drift, with multiple processes taking place at the same time. If a person thinks about a table, then a lot of related words will come to mind, too. And we thought that if we want to understand what is in a person’s mind when they think about anything concrete, we can follow those words.”

Pereira and his co-authors worked from fMRI images of brain activity that a team led by Just and fellow Carnegie Mellon researcher Tom Mitchell, a professor of computer science, published in the journal Science in 2008. For those scans, nine people were presented with the word and picture of five concrete objects from 12 categories. The drawing and word for the 60 total objects were displayed in random order until each had been shown six times. Each time an image and word appeared, participants were asked to visualize the object and its properties for three seconds as the fMRI scanner recorded their brain activity.

Princeton researchers developed a method to determine the probability of various words being associated with the object a person thought about during a brain scan. They produced color-coded figures that illustrate the probability of words within the Wikipedia article about the object the participant saw during the scan actually being associated with the object. The more red a word is, the more likely a person is to associate it, in this case, with "cow." On the other hand, bright blue suggests a strong correlation with "carrot." Black and grey "neutral" words had no specific association or were not considered at all. Credit: Courtesy of Francisco Pereira

The computer ultimately created a database of topics and associated words that were free from the researchers’ biases, Pereira said.

“We let the software discern the factors that make up meaning rather than stipulating it ourselves,” he said. “There is always a danger that we could impose our preconceived notions of the meaning words have. Plus, I can identify and describe, for instance, a bird, but I don’t think I can list all the characteristics that make a bird a bird. So instead of postulating, we let the computer find semantic threads in an unsupervised manner.”

The topic database let the researchers objectively arrange the fMRI images by subject matter, Pereira said. To do so, the team searched the brain scans of related objects for similar activity to determine common brain patterns for an entire subject, Pereira said. The neural response for thinking about “furniture,” for example, was determined by the common patterns found in the fMRI images for “table,” “chair,” “bed,” “desk” and “dresser.” At the same time, the team established all the words associated with “furniture” by matching each fMRI image with related words from the Wikipedia-based list.

Based on the similar brain activity and related words, Pereira, Botvinick and Detre concluded that the same neural response would appear whenever a person thought of any of the words related to furniture, Pereira said. And a scientist analyzing that brain activity would know that person was thinking of furniture. The same would follow for any topic.

Using images to predict the words on a person’s mind
Finally, to ensure their method was accurate, the researchers conducted a blind comparison of each of the 60 fMRI images against each of the others. Without knowing the objects the pair of scans pertained to, Pereira and his colleagues estimated the presence of certain topics on a participant’s mind based solely on the fMRI data. Knowing the applicable Wikipedia topics for a given brain image, and the keywords for each topic, they could predict the most likely set of words associated with the brain image.

The researchers found that they could confidently determine from an fMRI image the general topic on a participant’s mind, but that deciphering specific objects was trickier, Pereira said. For example, they could compare the fMRI scan for “carrot” against that for “cow” and safely say that at the time the participant had thought about vegetables in the first example instead of animals. In turn, they could say that the person most likely thought of other words related to vegetables, as opposed to words related to animals.

On the other hand, when the scan for “carrot” was compared to that for “celery,” Pereira and his colleagues knew the participant had thought of vegetables, but they could not identify related words unique to either object.

One aim going forward, Pereira said, is to fine-tune the group’s method to be more sensitive to such detail. In addition, he and Botvinick have begun performing fMRI scans on people as they read in an effort to observe the various topics the mind accesses.

“Essentially,” Pereira said, “we have found a way to generally identify mental content through the text related to it. We can now expand that capability to even further open the door to describing thoughts that are not amenable to being depicted with pictures.”

Material adapted from Princeton University.

Biomarkers such as changes in brain volume or in cerebrospinal fluid levels of some proteins have helped scientists learn about how Alzheimer’s disease develops and whether treatments for it are effective, according to background information in the article. Behavioral markers such as cognitive changes, genetic risk factors and demographic variables also seem to be associated with the condition. However, the authors write, “despite formidable evidence for the predictive validity of individual biomarkers and behavioral markers, they have rarely been examined in combined models.”

Jesus J. Gomar, Ph.D., from the Benito Menni Complex Assistencial en Salut Mental, Barcelona, Spain, and colleagues sought to determine how well different classes of biomarkers and cognitive markers could predict whether patients with MCI would develop Alzheimer’s disease. They also wanted to assess whether any of these factors was associated with a disproportionate magnitude of decline. The longitudinal study used information from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database. The study included 116 participants with MCI that converted to Alzheimer’s disease in two years, 204 participants with MCI that did not convert to Alzheimer’s disease and 197 cognitively healthy participants as controls.

The researchers used a variety of neuropsychological tests to assess participants’ cognition and ability to function. They obtained cerebrospinal fluid samples when the study began and at annual visits for two years. At the beginning of the study, participants gave a blood sample which was examined for the presence of genes associated with Alzheimer’s disease. The researchers also obtained information about participants’ brain volume and cortical thickness from magnetic resonance imaging results included in the ADNI.

Analysis of the variables showed that two measures of delayed memory, as well as the cortical thickness of the left middle temporal lobe in the brain, were associated with a higher chance of converting from MCI to Alzheimer’s disease at two years. A change in participants’ scores on a measure of functional activities appeared to show a larger rate of decline than did changes in biomarkers. In particular, a decline in scores on the Functional Assessment Questionnaire and the Trail Making Test, part B, appeared to predict whether an individual with MCI would develop Alzheimer’s disease within one year.

“Cognitive markers at baseline were more robust predictors of conversion than most biomarkers,” write the authors. “Longitudinal analyses suggested that conversion appeared to be driven less by changes in the neurobiologic trajectory of the disease than by a sharp decline in functional ability and, to a lesser extent, by declines in executive function.” The researchers add that in clinical practice and in clinical trials, the optimal way to accurately predict conversion to Alzheimer’s disease is to use all available data.

Material adapted from JAMA.

Reference
Arch Gen Psychiatry. 2011;68[9]:961-969. Available pre-embargo to the media at www.jamamedia.org.)

Researcher John Gabrieli

The new study, published in the journal NeuroImage, found that when the PHC was very active before people were shown an image, they were less likely to remember it later. “When that area is busy, for some reason or another, it’s less ready to learn something new,” says Gabrieli, the Grover Hermann Professor of Health Sciences and Technology and Cognitive Neuroscience and a principal investigator at the McGovern Institute for Brain Research at MIT.

The PHC, which has previously been linked to recollection of visual scenes, wraps around the hippocampus, a part of the brain critical for memory formation. However, this study is the first to investigate how PHC activity before a scene was presented would affect how well the scene was remembered. Lead author of the paper is Julie Yoo, a postdoc at the McGovern Institute.

Subjects were shown 250 color photographs of indoor and outdoor scenes as they lay in a functional magnetic resonance imaging (fMRI) scanner. They were later shown 500 scenes — including the 250 they had already seen — as a test of their recollection of the first batch of images. The fMRI scans revealed that images were remembered better when there was lower activity in the PHC before the scenes were presented.

The precise area of activation was slightly different in each person studied, but was always located in the PHC.

In a second experiment, the researchers used real-time fMRI, which can monitor subjects’ brain states from moment to moment, to determine when the brain was “ready” or “not ready” to recall images. Those states were used as triggers to present new visual scenes. As expected, images presented while the brain was in a “ready” state were better remembered.

In theory, this method could be used to determine when a student is best prepared to learn new material, or to monitor workers who need to stay alert. “That’s what we would like to think — that we are able to measure states of receptivity for learning, or preparedness for learning,” Gabrieli says. “In terms of how that would be translated to real life, there are still a few steps to go.”

The main hurdle is that fMRI scanners are very large, and at this point, they cannot be made into small, portable devices. A possible alternative is using electroencephalography (EEG), a more easily miniaturized technology that measures electrical activity along the scalp. The researchers are now working on ways to use EEG to measure activity in the PHC.

Material adapted from MIT.

The researchers showed that an electrical signal passing through a brain cell (neuron) results in the brain cell releasing the molecule glutamate. Glutamate, in turn, triggers another type of brain cell, called an oligodendrocyte, to form a point of contact with the neuron. Signals transmitted through this contact point stimulate the oligodendrocyte to make myelin protein and begin the process of myelination. In this process, the oligodendrocyte wraps myelin around axons— the long, cable-like projections that extend from each neuron. The myelination process is analogous to wrapping electrical tape around bare wires.

Electrical signals transmitted from one neuron to the next are a basic form of communication in the brain. The myelin layers that oligodendrocytes wrap around neurons boost these signals so that they travel 50 times faster than before.

The study was conducted by Hiroaki Wake, Philip R. Lee, and R. Douglas Fields of the Nervous System Development and Plasticity Section of the NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). Their findings appear online in Science Express.

“Insulation begins to form on axons in the late stages of fetal development, but the process continues through childhood, adolescence, and into early adulthood,” said Dr. Fields, the study’s senior author. “For example, infants cannot hold up their heads or walk until the appropriate motor axons become myelinated, and the frontal lobes of the brain, responsible for judgment and higher-level complex reasoning, are not fully myelinated until the early twenties.”

Understanding how oligodendrocytes generate and help repair myelin could provide insight into how only the appropriate axons in the brain become insulated during development as people acquire skills, with the eventual goal of helping them do so more efficiently, Dr. Fields explained. Similarly, understanding the myelination process could lead to insights into disorders like multiple sclerosis, in which myelin is either damaged or destroyed. Moreover, understanding myelination may allow researchers to speed myelination— and repair— of axons recovering from injury.

Throughout the brain, oligodendrocytes and neurons exist side by side. The researchers placed mouse nerve cells and myelin-making oligodendrocytes together in a dish and stimulated the nerve cells with electrical pulses. After three weeks, they found that the nerve cells were wrapped in a myelin covering.

In a separate culture of neurons and oligodendrocytes, the researchers blocked the release of the molecule glutamate, a neurotransmitter. Neurotransmitters make it possible for signals to pass between cells. When glutamate release was blocked, very little myelin coating formed. Further experiments showed that after the electrical pulses and the release of glutamate, nerve cells and the neighboring oligodendrocytes began sending chemical signals back and forth. Then the oligodendrocytes started to make the protein used to form the myelin sheath. Specifically, receptors on the cell membrane of oligodendrocytes detect glutamate released by the axon, and this triggers the formation of what the researchers termed specialized adhesive signaling junctions—points of contact between oligodendrocytes and axons that enable signals to be passed between the cells. Then the oligodentrocytes began depositing myelin on electrically active axons, but not on axons that were not electrically active.

“This shows that axons that are transmitting electrical signals will become preferentially insulated by myelin,” Dr. Fields said.

In a previous study, Dr. Fields and his coauthors found that electrical activity in neurons stimulates other cells, called astrocytes, that also are involved in the myelination process.

Material adapted from NIH.

Researcher Marcel Just

A new brain imaging study published in the journal “Brain” by scientists at Carnegie Mellon University provides an explanation as to why autistic individuals’ use of the wrong pronoun is more than simply a word choice problem. Marcel Just, Akiki Mizuno and their collaborators at CMU’s Center for Cognitive Brain Imaging (CCBI) found that errors in choosing a self-referring pronoun reflect a disordered neural representation of the self, a function processed by at least two brain areas — one frontal and one posterior.

“The psychology of self — the thought of one’s own identity — is especially important in social interaction, a facet of behavior that is usually disrupted in autism,” said Just, a leading cognitive neuroscientist and the D.O. Hebb Professor of Psychology at CMU who directs the CCBI. “Most children don’t need to receive any instruction in which pronoun to use. It just comes naturally, unless a child has autism.”

For the study, the research team used functional magnetic resonance imaging (fMRI) to compare the brain activation pattern and the synchronization of activation across brain areas in young adults with high-functioning autism with control participants during a language task that required rapid pronoun comprehension.

The results revealed a significantly diminished synchronization in autism between a frontal area (the right anterior insula) and a posterior area (precuneus) during pronoun use in the autism group. The participants with autism also were slower and less accurate in their behavioral processing of the pronouns. In particular, the synchronization was lower in autistic participants’ brains between the right anterior insula and precuneus when answering a question that contained the pronoun “you,” querying something about the participant’s view.

“Shifting from one pronoun to another, depending on who the speaker is, constitutes a challenge not just for children with autism but also for adults with high-functioning autism, particularly when referring to one’s self,” Just said. “The functional collaboration of two brain areas may play a critical role for perspective shifting by supporting an attention shift between oneself and others.

“Pronoun reversals also characterize an atypical understanding of the social world in autism. The ability to flexibly shift viewpoints is vital to social communication, so the autistic impairment affects not just language but social communication,” Just added.

Autism was documented for the first time in 1943, in a landmark article by Dr. Leo Kanner of Johns Hopkins University. In that first article, Kanner noted the puzzling misuse of pronouns by children with the disorder. “When he [the child] wanted his mother to pull his shoe off, he said: ‘Pull off your shoe.’” Kanner added that, “Personal pronouns are repeated [by the child with autism] just as heard, with no change to suit the altered situation.” Because his mother referred to him as “you,” so did the child.

Just’s previous brain imaging research in autism has shown that other facets of thinking that are disrupted in autism, such as social difficulties and language impairments, also may be attributed to a reduced communication bandwidth between the frontal and posterior parts of the brain. He refers to this as the “Theory of Frontal-Posterior Underconnectivity.” In each of these types of thinking, the processing is done by a set of different brain regions that includes key frontal regions, and the lower frontal-posterior bandwidth limits how well the frontal regions can contribute to the brain’s networked computations.

The brain’s communication network is its white matter, the 45 percent of the brain that consists of myelinated (insulated) axons that carry information between brain regions. An emerging view is that the white matter is compromised in autism, specifically in the frontal-posterior tracts. In a groundbreaking study published in 2009, Just and his colleagues showed for the first time that compromised white matter in children with reading difficulties could be repaired with extensive behavioral therapy. Their imaging study showed that the brain locations that had been abnormal prior to the remedial training improved to normal levels after the training, and the reading performance in individual children improved by an amount that corresponded to the amount of white matter change. Ongoing research at the CCBI is assessing the white matter in detail, measuring its integrity and topology, trying to pinpoint the difference in the autistic brain’s networks.

“This new understanding of what causes pronoun confusion in autism helps make sense of the larger problems of autism as well as the idiosyncrasies,” Just said. “Moreover, it points to new types of therapies that may help rehab the white matter in autism.”

In addition to Just and Mizuno, a psychology doctoral candidate and first author of the study, the research team included CMU’s Yanni Liu, a postdoctoral associate, and Timothy A. Keller, a senior research psychologist; Duquesne University’s Diane L. Williams, an assistant professor of speech-language pathology; and the University of Pittsburgh School of Medicine’s Nancy J. Minshew, a professor of psychiatry and neurology.

Material adapted from Carnegie Mellon University.

Researcher Charles DeCarli, M.D.

“This study provides evidence that identifying these risk factors early in middle age could be useful in screening people at risk of dementia and in encouraging them to make changes in their lifestyles before it’s too late,” said Charles DeCarli, a professor of neurology in the UC Davis School of Medicine and director of the UC Davis Alzheimer’s Disease Center.

The study examined the relationships between midlife vascular risk factors and markers for brain aging based on magnetic resonance imaging (MRI). The indicators are associated with cognitive decline and dementia later in life.

The current study was conducted with data from participants in the Framingham Offspring Cohort Study, a multi-site, prospective cohort study comprised of three generations of the offspring and spouses of participants in the Framingham Heart Study. Some 1,352 of the study participants were included in the current research. The study subjects had an average age of 54.

Study participants have been followed since 1978 to identify vascular disease risk factors, and were repeatedly assessed for those risk factors, which included an elevated body mass index, hypertension, obesity, diabetes and smoking.

Beginning in 1999, the researchers obtained measures of vascular disease such as the volume of white matter hyperintensities, or areas on MRI that appear bright white that are associated with increased vascular damage. Other measurements included changes in total brain volume and changes in cognitive tests of verbal and spatial memory and decision-making capabilities.

The study found that people with high blood pressure developed white matter hyperintensities at a faster rate than those with normal blood pressure and had a more rapid decline in scores on tests of executive function, or planning and decision making. Participants who were obese were more likely to be in the top 25 percent of people with a greater rate of decline in scores on tests of executive functioning abilities later in life.

The study also found that participants with diabetes in mid-life had lost brain volume in the hippocampus brain region at a faster rate than those without diabetes when they were older. Study subjects who smoked lost overall brain volume faster than non-smokers and also were more likely to have a rapid increase in white matter hyperintensities.

“These factors appeared to cause the brain to lose volume, to develop lesions secondary to presumed vascular injury, and also appeared to affect the brain’s ability to plan and make decisions as quickly as it had 10 years earlier,” said DeCarli, who is a fellow of the American Academy of Neurology.

Other study authors include Stephanie Debette, Sudha Seshadri, Alexa Besier, Jayandra Jung Himali, Carole Palumbo and Philip A. Wolf, all of Boston University.

Material adapted from UC Davis Health System.

Over twenty years ago, a team of scientists, led by Giacomo Rizzolatti at the University of Parma, discovered special brain cells, called mirror neurons, in monkeys. These cells appeared to be activated both when the monkey did something itself and when the monkey simply watched another monkey do the same thing.

The function of such mirror neurons in humans has since become a hot topic. In the latest issue of Perspectives on Psychological Science, a team of distinguished researchers debate whether the mirror neuron system is involved in such diverse processes as understanding speech, understanding the meaning of other people’s actions, and understanding other people’s minds.

Understanding Speech
The mirror neuron system probably plays some role in how we understand other people’s speech, but it’s likely that this role is much smaller than has been previously claimed. In fact, the role is small enough that it’s unlikely that mirror neurons would be causal factors in our ability to understand speech. Mirror neuron-related processes may only contribute to understanding what another person is trying to say if the room is very noisy or there are other complications to normal speech perception conditions.

Understanding Actions
Mirror neurons are believed to play a critical role in how and why we understand other people’s actions. There are many physical actions, like Tiger Woods’ golf swing, that we ourselves can’t do, but we understand those actions anyway. However, contrary to what some mirror neuron proponents have suggested, doing isn’t required for understanding. In fact, neuroimaging data reviewed in this article demonstrate that the actions we ourselves have the most experience doing — the actions we are best at doing and understand best — actually show less mirror neuron activity. Such findings suggest a need to reappraise the role of mirror neurons in guiding how we understand actions.

Understanding Minds
One of the most powerful roles suggested for the mirror neuron system in humans is that of understanding not just other people’s physical actions or speech, but their minds and their intentions. It has been suggested that some persons, such as persons with autism, have difficulty understanding other people’s minds and, therefore, might lack mirror neurons. However, numerous research studies reviewed in this article consistently show that persons with autism are highly capable of understanding the intentions of other people’s actions, suggesting that our intuitions about persons with autism and mirror neurons needs to be revised.

This article presents some of the toughest questions asked about mirror neurons to date. The answers to those questions, guided by hundreds of research studies, clarify the limits of the function of mirror neurons in humans.

Material adapted from Association for Psychological Science.

Researcher Charles DeCarli, M.D.

“These factors appeared to cause the brain to lose volume, to develop lesions secondary to presumed vascular injury, and also appeared to affect its ability to plan and make decisions as quickly as 10 years later. A different pattern of association was observed for each of the factors,” said study author Charles DeCarli, MD, with the University of California at Davis in Sacramento and a Fellow of the American Academy of Neurology. “Our findings provide evidence that identifying these risk factors early in people of middle age could be useful in screening people for at-risk dementia and encouraging people to make changes to their lifestyle before it’s too late.”

The study involved 1,352 people without dementia from the Framingham Offspring Study with an average age of 54. Participants had body mass and waist circumference measures taken and were given blood pressure, cholesterol and diabetes tests. They also underwent brain MRI scans over the span of a decade, the first starting about seven years after the initial risk factor exam. Participants with stroke and dementia at baseline were excluded, and between the first and last MRI exams, 19 people had a stroke and two developed dementia.

The study found that people with high blood pressure developed white matter hyperintensities, or small areas of vascular brain damage, at a faster rate than those with normal blood pressure readings and had a more rapid worsening of scores on tests of executive function, or planning and decision making, corresponding to five and eight years of chronological aging respectively.

People with diabetes in middle age lost brain volume in the hippocampus (measured indirectly using a surrogate marker) at a faster rate than those without diabetes. Smokers lost brain volume overall and in the hippocampus at a faster rate than nonsmokers and were also more likely to have a rapid increase in white matter hyperintensities.

People who were obese at middle age were more likely to be in the top 25 percent of those with the faster rate of decline in scores on tests of executive function, DeCarli said. People with a high waist-to-hip ratio were more likely to be in the top 25 percent of those with faster decrease in their brain volume.

The study was supported by the National Heart, Lung, and Blood Institute, the National Institute of Neurological Disorders and Stroke and the National Institute on Aging.

Material adapted from American Academy of Neurology (AAN).

Researcher Amy Arnsten, PhD

“Age-related cognitive deficits can have a serious impact on our lives in the Information Age as people often need higher cognitive functions to meet even basic needs, such as paying bills or accessing medical care,” said Amy Arnsten, Professor of Neurobiology and Psychology and a member of the Kavli Institute for Neuroscience. “These abilities are critical for maintaining demanding careers and being able to live independently as we grow older.”

As people age, they tend to forget things more often, are more easily distracted and disrupted by interference, and have greater difficulty with executive functions. While these age-related deficits have been known for many years, the cellular basis for these common cognitive difficulties has not been understood. The new study examined for the first time age-related changes in the activity of neurons in the prefrontal cortex (PFC), the area of the brain that is responsible for higher cognitive and executive functions.

Networks of neurons in the prefrontal cortex generate persistent firing to keep information “in mind” even in the absence of cues from the environment. This process is called “working memory,” and it allows us to recall information, such as where the car keys were left, even when that information must be constantly updated. This ability is the basis for abstract thought and reasoning, and is often called the “Mental Sketch Pad.” It is also essential for executive functions, such as multi-tasking, organizing, and inhibiting inappropriate thoughts and actions.

Arnsten and her team studied the firing of prefrontal cortical neurons in young, middle-aged and aged animals as they performed a working memory task. Neurons in the prefrontal cortex of the young animals were able to maintain firing at a high rate during working memory, while neurons in older animals showed slower firing rates. However, when the researchers adjusted the neurochemical environment around the neurons to be more similar to that of a younger subject, the neuronal firing rates were restored to more youthful levels.

Arnsten said that the aging prefrontal cortex appears to accumulate excessive levels of a signaling molecule called cAMP, which can open ion channels and weaken prefrontal neuronal firing. Agents that either inhibited cAMP or blocked cAMP-sensitive ion channels were able to restore more youthful firing patterns in the aged neurons. One of the compounds that enhanced neuronal firing was guanfacine, a medication that is already approved for treating hypertension in adults, and prefrontal deficits in children, suggesting that it may be helpful in the elderly as well.

Arnsten’s finding is already moving to the clinical setting. Yale is enrolling subjects in a clinical trial testing guanfacine’s ability to improve working memory and executive functions in elderly subjects who do not have Alzheimer’s Disease or other dementias.

For detailed information about this clinical trial, go here http://clinicaltrials.gov/ct2/show/NCT00935493

Material adapted from Yale University.

Now, in the August issue of Current Directions in Psychological Science, a journal published by the Association for Psychological Science, University of Edinburgh cognitive neuroscientist Robert H. Logie challenges this model.

“We have a range of different capacities, each with its own function, and they operate at the same time” when we perform a task or think about something, says Logie. Within this “multiple-component framework,” working memory capacity is “the sum of the capacities of all these different functions.”

This “workspace” in the brain, as Logie calls it, allows us to do something while other functions operate in the background or to apply ourselves to a single task involving more than one function. In reading, for instance, we both see words and process meaning. The “sum” of the capacities isn’t a gross measure, though, because we often tax one function more than another. In reading, processing has its shoulder to the grindstone, while vision takes it easy.

In addition to the attentional model of working memory, Logie critiques the experimental methods shaped by it. Example: Studies measuring capacity ask participants to read a sentence (process) and remember the sentence’s last word (memory), then read several sentences and recall all the final words in order. How well a person does can predict performance on other tasks or exams. But the experiment, which assumes one big resource pouring into different tasks until it is used up, tests only one function, memory for words.

If you want to understand not just the capacity but the structure of working memory — which Logie considers a more fruitful avenue of research — there is a better experimental methodology: cognitive neuroscience.

“Imaging data demonstrate that if you ask people to do one sort of task, you get one [brain] pattern, and if you ask them to do another, you get another pattern.” Make the same task harder — say, remember word lists faster — and “you see increased activation in the same area.” Complicate it — add words to the sequence, and thus processing along with recall — and different networks fire.

The multiple-component model holds great practical promise, says Logie. In education, “if you assume there is a single general capacity,” interventions for people struggling to learn are few. Assume multiple components to draw on, and those other resources stand ready for development.

Similarly, if you see general impairment in aging or after brain damage, you can give only generalized support. Look for decline or impairment in specific functions—not just physical but cognitive—and you can exercise the still-robust functions, helping people live richer, more independent lives.

Material adapted from Association for Psychological Science.

Driving at 100km/h, this amounts to reducing the braking distance by 3.66 meters – the full length of a compact car or the potential margin between causing and avoiding accidents.

The study, published today, 29 July 2011, in IOP Publishing’s Journal of Neural Engineering, identified the parts of the brain that are most active when braking and used a driving simulator to demonstrate the viability of mind-reading assisted driving.

As well as EEG, the researchers, from the Berlin Institute for Technology, also chose to examine myoelectric (EMG) activity which is caused by muscle tension in the lower leg and can be used to detect leg motion before it actually moves to the brake pedal.

Whilst sat among conventional driving controls, the study’s 18 participants were asked to drive a car that was displayed on a screen in front of them whilst a series of electrodes were attached to their scalp to measure brain activity.

They were asked to stay within a 20 metre distance of a computer-controlled lead vehicle along a road that contained sharp curves and dense oncoming traffic, to recreate real driving conditions, whilst maintaining a speed of 100km/h.

At random intervals, emergency braking situations were triggered by the rapid braking of the lead vehicle in front, accompanied by the flashing of its braking lights.

At this point, when the subjects reacted, the data was collected from the EEG and EMG. For comparison, the researchers also recorded information on the time it took to release the gas pedal and press the brake pedal, the deceleration of both vehicles and the distance between the two vehicles.

Using the initial EEG recordings, the researchers were able to determine what parts of the brain are most sensitive in a braking scenario and therefore tweak the detection system accordingly.

A recent development, implemented into this study, are hybrid systems where external lasers and sensors are able to sense when a potential crash is upcoming so that as soon as the break pedal is touched, the vehicles goes into an emergency braking procedure; however these systems still rely on a human physical response, which is where a mind-reading system could benefit.

Lead author of the study Stefan Haufe said, “Averaged over all potential detection thresholds, a system that uses all available sensors detects emergency situations 130 milliseconds earlier than a system that doesn’t use EEG and EMG. We can safely say that it is mainly EEG that leads to the early detection.”

“We are now considering to test the system online in a real car however if such a technology would ever enter a commercial product, it would certainly be used to complement other assistive technology to avoid the consequences of false alarms that could be both annoying and dangerous.”

Material adapted from Institute of Physics.

Download / Reference
Haufe et al. (2011). “EEG potentials predict upcoming emergency brakings during simulated driving.” J. Neural Eng. 8 056001.

“We are on track to develop, test and make available to the public- within the next few years – a safe, reliable, noninvasive brain computer interface that can bring life-changing technology to millions of people whose ability to move has been diminished due to paralysis, stroke or other injury or illness,” said Contreras-Vidal of the university’s School of Public Health.

Harsha Agashe, a Ph.D. student in Contreras-Vidal's lab wears the Brain Cap, a non-invasive, sensor-lined cap with neural interface software. Photo Credit - John Consoli, University of Maryland.

“We are doing something that few previously thought was possible,” said Contreras-Vidal, who is also an affiliate professor in Maryland’s Fischell Department of Bioengineering and the university’s Neuroscience and Cognitive Science Program. “We use EEG [electroencephalography] to non-invasively read brain waves and translate them into movement commands for computers and other devices.

Peer Reviewed
Contreras-Vidal and his team have published three major papers on their technology over the past 18 months, the latest a just released study in the Journal of Neurophysiology in which they successfully used EEG brain signals to reconstruct the complex 3-D movements of the ankle, knee and hip joints during human treadmill walking. In two earlier studies they showed (1) similar results for 3-D hand movement and (2) that subjects wearing the brain cap could control a computer cursor with their thoughts.

Alessandro Presacco, a second-year doctoral student in Contreras-Vidal’s Neural Engineering and Smart Prosthetics Lab, Contreras-Vidal and co-authors write that their Journal of Neurophysiology study indicated “that EEG signals can be used to study the cortical dynamics of walking and to develop brain-machine interfaces aimed at restoring human gait function.”

There are other brain computer interface technologies under development, but Contreras-Vidal notes that these competing technologies are either very invasive, requiring electrodes to be implanted directly in the brain, or, if noninvasive, require much more training to use than does UMD’s EEG-based, brain cap technology.

Partnering to Help Sufferers of Injury and Stroke 
Contreras-Vidal and his team are collaborating on a rapidly growing cadre projects with researchers at other institutions to develop thought-controlled robotic prosthetics that can assist victims of injury and stroke. Their latest partnership is supported by a new $1.2 million NSF grant. Under this grant, Contreras-Vidal’s Maryland team is embarking on a four-year project with researchers at Rice University, the University of Michigan and Drexel University to design a prosthetic arm that amputees can control directly with their brains, and which will allow users to feel what their robotic arm touches.

“There’s nothing fictional about this,” said Rice University co-principal investigator Marcia O’Malley, an associate professor of mechanical engineering. “The investigators on this grant have already demonstrated that much of this is possible. What remains is to bring all of it – non-invasive neural decoding, direct brain control and [touch] sensory feedback – together into one device.”

In a NIH-supported project underway, Contreras-Vidal and his colleagues are pairing their brain cap’s EEG-based technology with a DARPA-funded next-generation robotic arm designed by researchers at the Johns Hopkins Applied Physics Laboratory to function like a normal limb. And the UMD team is developing a new collaboration with the New Zealand’s start-up Rexbionics, the developer of a powered lower-limb exoskeleton called Rex that could be used to restore gait after spinal cord injury.

During research at the Veterans Affairs Medical Center in Baltimore, Alessandro Presacco, a graduate researcher in UMD's Neural Engineering and Smart Prosthetics Lab, gets hooked up to take data similar to that used to reconstruct the complex 3-D movements of the ankle, knee and hip joints during treadmill walking. Photo Credit - University of Maryland.

“There is a big push in brain science to understand what exercise does in terms of motor learning or motor retraining of the human brain,” says Larry Forrester, an associate professor of physical therapy and rehabilitation science at the University of Maryland School of Medicine.

For the more than a year, Forrester and the UMD team have tracked the neural activity of people on a treadmill doing precise tasks like stepping over dotted lines. The researchers are matching specific brain activity recorded in real time with exact lower-limb movements.

This data could help stroke victims in several ways, Forrester says. One is a prosthetic device, called an “anklebot,” or ankle robot, that stores data from a normal human gait and assists partially paralyzed people. People who are less mobile commonly suffer from other health issues such as obesity, diabetes or cardiovascular problems, Forrester says, “so we want to get [stroke survivors] up and moving by whatever means possible.”

The second use of the EEG data in stroke victims is more complex, yet offers exciting possibilities. “By decoding the motion of a normal gait,” Contreras-Vidal says, “we can then try and teach stroke victims to think in certain ways and match their own EEG signals with the normal signals.” This could “retrain” healthy areas of the brain in what is known as neuroplasticity.

One potential method for retraining comes from one of the Maryland research team’s newest members, Steve Graff, a first-year bioengineering doctoral student. He envisions a virtual reality game that matches real EEG data with on-screen characters. “It gives us a way to train someone to think the right thoughts to generate movement from digital avatars. If they can do that, then they can generate thoughts to move a device,” says Graff, who brings a unique personal perspective to the work. He has congenital muscular dystrophy and uses a motorized wheelchair. The advances he’s working on could allow him to use both hands – to put on a jacket, dial his cell phone or throw a football while operating his chair with his mind.

Alessandro Presacco, a graduate researcher in UMD's Neural Engineering and Smart Prosthetics Lab, adjust a version of Brain Cap headset worn by Steve Graff, a bioengineering doctoral student . Looking on is Lab director and Brain Cap creator José 'Pepe' Contreras-Vidal. Photo Credit - University of Maryland.

No Surgery Required
During the past two decades a great deal of progress has been made in the study of direct brain to computer interfaces, most of it through studies using monkeys with electrodes implanted in their brains. However, for use in humans such an invasive approach poses many problems, not the least of which is that most people don’t’ want holes in their heads and wires attached to their brains.

“EEG monitoring of the brain, which has a long, safe history for other applications, has been largely ignored by those working on brain-machine interfaces, because it was thought that the human skull blocked too much of the detailed information on brain activity needed to read thoughts about movement and turn those readings into movement commands for multi-functional high-degree of freedom prosthetics,” said Contreras-Vidal. He is among the few who have used EEG, MEG or other sensing technologies to develop non-invasive neural interfaces, and the only one to have demonstrated decoding results comparable to those achieved by researchers using implanted electrodes.

A paper Contreras-Vidal and colleagues published in the Journal of Neuroscience in March 2010 showed the feasibility of Maryland’s EEG-based technology to infer multidimensional natural movement from noninvasive measurements of brain activity. In their two latest studies, Contreras-Vidal and his team have further advanced the development of their EEG brain interface technology, and provided powerful new evidence that it can yield brain computer interface results as good as or better than those from invasive studies, while also requiring minimal training to use.

In a paper published in April in the Journal of Neural Engineering, the Maryland team demonstrated that people wearing the EEG brain cap, could after minimal training control a computer cursor with their thoughts and achieve performance levels comparable to those by subjects using invasive implanted electrode brain computer interface systems. Contreras-Vidal and his co-authors write that this study also shows that compared to studies of other noninvasive brain control interface systems, training time with their system was substantially shorter, requiring only a single 40-minute session.

Material adapted from University of Maryland, College Park.

The benefits of body-language mimicry have been confirmed by numerous psychological studies. And in popular culture, mirroring is frequently urged on people as a strategy – for flirting or having a successful date, for closing a sale, or acing a job interview. But new research suggests that mirroring may not always lead to positive social outcomes. In fact, sometimes the smarter thing to do is to refrain.

In a study to be published in a forthcoming issue of Psychological Science, Piotr Winkielman and Liam Kavanagh of the psychology department at the University of California, San Diego, along with philosophers Christopher Suhler and Patricia Churchland, also of UC San Diego, note that in real-life situations there are often observers to the mirroring that takes place between two people. This led them to wonder whether mimicry sometimes comes at a reputational cost. Are there cases in which an observer might actually think less of a person for mirroring the behavior of another?

Results of three experiments suggest that mimicry is more nuanced than previously thought and not, the authors write, “uniformly beneficial to the mimicker.”

“Mimicry is a crucial part of social intelligence,” said Winkielman, UC San Diego professor of psychology. “But it is not enough to simply know how to mimic. It’s also important to know when and when not to. The success of mirroring depends on mirroring the right people at the right time for the right reasons. Sometimes the socially intelligent thing to do is not to imitate.”

A person was judged as less competent when mimicking an unfriendly interviewer. When the mimicry was obscured from view, the reputational cost disappeared. Credit: Courtesy Piotr Winkielman, UC San Diego

Despite the fact that the participants were not instructed to watch for mimicry and reported no awareness of it, it still influenced their evaluations: Interviewees who mimicked the unfriendly interlocutor were judged to be less competent than those who did not. That is to say, in the eyes of the outside observers, the imitators of the undesirable model incurred reputational costs – their unconsciously observed mirroring registered as a kind of error.

In a second corollary experiment, participants were exposed to the same videos but with the interviewer obscured. In other words, they could not see any evidence of mimicry, and the results support the researchers’ hypothesis: It is not merely interacting with negatively perceived people that has a social cost; you pay a price for aligning with them through body language.

Interestingly, an additional experiment showed that the reputational cost of mimicking an unfriendly interviewer disappeared when participants read positive information about that interviewer – i.e., that he was engaged in humanitarian work – before watching the video. “It’s almost as though mimicry of a condescending interviewer was forgiven when he was judged to be good at heart,” Winkielman said.

Our social lives are incredibly complex, said Winkielman, and in order to build or maintain relationships we have to keep in mind a variety of factors. “It’s good to have the capacity to mimic,” he said, “but an important part of social intelligence is knowing how to deploy this capacity in a selective, intelligent, context-dependent manner, and understanding, even implicitly, when mirroring can reflect badly on you.”

Material adapted from University of California – San Diego.

Researcher Mauricio Delgado

“Everything we do involves making choices, even if we don’t think very much about it. For example, just moving your leg to walk in one direction or another is a choice – however, you might not appreciate that you are choosing this action, unless someone were to stop you from moving that leg. We often take for granted all of the choices we make, until they are taken away,” says Mauricio Delgado at Rutgers University, who co-wrote the article along with post-doctoral fellow, Lauren Leotti.

In conducting their experiment, Leotti and Delgado used a simple task in which participants were presented with different cues – the choice and no choice cues. The choice cue represented an opportunity for choice, where participants could pick two options, and the no choice cue represented a condition where the computer would choose for them. In both the choice and no-choice conditions, participants had the opportunity to win money, though the outcomes were not actually contingent on their responses. Nonetheless, participants tended to perceive control over the outcomes when they were given the opportunity to exercise choice.

According to Leotti, the study demonstrated that the opportunity for a sense of control relayed by the choice cues (compared to no choice cues) recruits reward related brain circuitry. “It makes sense that we would evolve to find choice rewarding, since the perception of control is so adaptive. If we didn’t feel that we were capable of effectively acting on our environment to achieve our desired goals, there would be little incentive to face even the slightest challenge,” says Leotti.

The research into the perception of control is especially relevant from a social aspect as it is important and valuable to psychological well-being. “It is at the crux of so many psychiatric disorders such as anxiety disorders, eating disorders, and substance abuse,” says Delgado who hopes to continue this line of research by investigating contextual influences on the value of choice in the near future. Furthermore, by understanding the neural bases of perception of control, it may be possible to target effective therapeutic treatments focusing on choice valuation and treat disruptions to perceived control, the root of many behavioral disorders.

So the next time you are faced with making a decision, from something as simple as choosing a blue or black tie for a business meeting to something as complex as putting down a deposit for a house (near your parents no less)… ask yourself – who’s in control?

Material adapted from Association for Psychological Science.

It is clear that time and numbers are related in daily life, says Denise Wu of National Central University of Taiwan, who cowrote the new study with Acer Chang, Ovid Tzeng, and Daisy Hung. Numbers are used to represent distance and size, and to go to a farther place usually takes a longer time, for example. But, she says, “Because the tradition of psychology is to manipulate one key variable of interest while controlling other confounding variables as much as possible, these domains were treated independently.” Recently, more researchers have started looking at how time and numbers are associated. Wu and her coauthors wanted to look more closely at this relationship, so they came up with a way to look at how numbers interfere with people’s perception of time.

In one experiment, each participant sat in front of a computer screen while a single-digit number appeared on the screen for a short time less than a second. After the number disappeared, the word “NOW” appeared on the screen, and the participant was supposed to hold down a key on the keyboard for as long as they thought the number had been displayed. The interaction between time and number was clear: after seeing a large number, like 9, people held the key down for longer than they did for a smaller number, like 2.

In another experiment, people saw a green dot for a short time. When they were asked to press the key, their key-press responses were accompanied by a number on the screen. In that case, they held down the key longer if they saw a small number and for a shorter time if they saw a large number. Wu thinks that happens because the small number makes people think they haven’t held down the key for long enough yet.

“We are really excited about this because this means the influence of the digit is so automatic and so immediate,” she says. The results suggest that the brain somehow processes time and the size of numbers together—possibly even with the same neurons. So, maybe instead of having different parts of the brain devoted to different kinds of measurement, there’s some part of the brain that is generally responsible for thinking about magnitude.

“It shows that it’s not like, mentally, we have a clock and it is immune to all the other information,” Wu says. Instead, your concept of time is responding to other things going on in the brain. In this case, it’s numbers, but it might also be influenced by emotion. For example, we all know that time passes more slowly in a boring meeting than when you’re chatting with a friend; maybe this is related to the ways that timekeeping links to other functions in the brain.

Material adapted from Association for Psychological Science.

The research was conducted by professor Michael Kahana of the Department of Psychology in the School of Arts and Sciences and graduate student Jeremy R. Manning, of the Neuroscience Graduate Group in Penn’s Perelman School of Medicine. They collaborated with Gordon Baltuch and Brian Litt of the departments of Neurology and Psychology at the medical school and Sean M. Polyn of Vanderbilt University.

“Theories of episodic memory suggest that when I remember an event, I retrieve its earlier context and make it part of my present context,” Kahana said. “When I remember my grandmother, for example, I pull back all sorts of associations of a different time and place in my life; I’m also remembering living in Detroit and her Hungarian cooking. It’s like mental time travel. I jump back in time to the past, but I’m still grounded in the present.”

To investigate the neurobiological evidence for this theory, the Penn team combined a centuries-old psychological research technique — having subjects memorize and recall a list of unrelated words — with precise brain activity data that can only be acquired via neurosurgery.

A diagram of electrode placements.

“We can do direct brain recordings in monkeys or rats, but with humans one can only obtain these recordings when neurosurgical patients, who require implanted electrodes for seizure mapping, volunteer to participate in memory experiments,” Kahana said. “With these recordings, we can relate what happens in the memory experiment on a millisecond-by-millisecond basis to what’s changing in the brain.”

The memory experiment consisted of patients memorizing lists of 15 unrelated words. After seeing a list of the words in sequence, the subjects were distracted by doing simple arithmetic problems. They were then asked to recall as many words as they could in any order. Their implanted electrodes measured their brain activity at each step, and each subject read and recalled dozens of lists to ensure reliable data.

“By examining the patterns of brain activity recorded from the implanted electrodes,” Manning said, “we can measure when the brain’s activity is similar to a previously recorded pattern. When a patient recalls a word, their brain activity is similar to when they studied the same word. In addition, the patterns at recall contained traces of other words that were studied prior to the recalled word.”

“What seems to be happening is that when patients recall a word, they bring back not only the thoughts associated with the word itself but also remnants of thoughts associated with other words they studied nearby in time,” he said.

The findings provide a brain-based explanation of a memory phenomenon that people experience every day.

“This is why two friends you met at different points in your life can become linked in your memory,” Kahana said. “Along your autobiographical timeline, contextual associations will exist at every time scale, from experiences that take place over the course of years to experiences that take place over the course of minutes, like studying words on a list.”

Material adapted from University of Pennsylvania.

According to background information provided in the articles, previous research has suggested that physical activity is associated with reduced rates of cognitive impairment in older adults. However, much of this research has apparently been conducted among individuals who are generally in good health. Further, many of these studies rely on self-reports of physical activity, which are not always accurate; and focus on moderate or vigorous exercise, instead of low-intensity physical activity. The two articles being presented today seek to fill in these gaps in the research.

In one article, Marie-Noël Vercambre, Ph.D., from the Foundation of Public Health, Mutuelle Generale de l’Education Nationale, Paris, and colleagues examined data from the Women’s Antioxidant Cardiovascular Study, which included women who had either prevalent vascular disease or three or more coronary risk factors. The researchers determined patients’ physical activity levels at baseline (1995 to 1996) and every two years thereafter. Between 1998 and 2000, they conducted telephone interviews with 2,809 women; the calls included tests of cognition, memory and category fluency, and followed up the tests three more times over the succeeding 5.4 years.

The researchers analyzed data to correlate cognitive score changes with total physical activity and energy expenditure from walking. As participants’ energy expenditure increased, the rate of cognitive decline decreased. The amount of exercise equivalent to a brisk, 30-minute walk every day was associated with lower risk of cognitive impairment.

In another report, Laura E. Middleton, Ph.D., from the Heart and Stroke Foundation Centre for Stroke Recovery, Sunnybrook Research Institute, Toronto, and colleagues utilized data from the Health, Aging, and Body Composition study, an ongoing prospective cohort study. The researchers measured participants’ total energy expenditure by using doubly labeled water, a technique that provides evidence of how much water a person loses and thus serves as an objective measure of metabolic activity. The authors calculated participants’ activity energy expenditure (AEE), defined as 90 percent of total energy expenditure minus resting metabolic rate. The 197 participants, with an average age of 74.8 years, had no mobility or cognitive problems when the research began in 1998 to 1999. At that time, researchers assessed participants’ cognitive function, and followed up two to five years later with the Modified Mini-Mental State Examination (MMMSE).

The authors adjusted the data for baseline MMMSE scores, demographics, fat-free mass, sleep duration, self-reported health and diabetes mellitus. When these variables were accounted for, participants who had the highest AEE scores tended to have lower odds of incident cognitive impairment. The authors also noticed a significant dose response between AEE and incidence of cognitive impairment.

The authors of both articles suggest that there is more to be learned about the relationship between physical activity and cognitive function. “Various biologic mechanisms may explain the positive relation between physical activity and cognitive health,” write Vercambre and colleagues. Middleton and co-authors state, “The mechanisms by which physical activity is related to late-life cognition are likely to be multifactorial.” Both groups of researchers note that studies such as theirs point toward some possible answers. As Vercambre and co-authors comment, “If confirmed in future studies, physical activity recommendations could yield substantial public health benefits given the growing number of older persons with vascular conditions and their high risk of cognitive impairment.” And Middleton and colleagues conclude, “We are optimistic that even low-intensity activity of daily living may be protective against incident cognitive impairment.”

Material adapted from JAMA.

Reference
Arch Intern Med. Published July 19, 2011. doi:10.1001/archinternmed.2011.282; doi:10.1001/archinternmed.2011.277.

We seem to have an innate preference for the familiar and research suggests that the recognition heuristic usually works in our favor, at least when it comes to things like predicting tennis matches.

But, according to his colleague Timm Rosburg, research still has not determined whether it is really “pure recognition” or something else that drives our preference for familiar over unknown options. So Rosburg, Frings and memory researcher Axel Mecklinger at Saarland University designed a study to explore the neurocognitive mechanisms that underlie the recognition heuristic. Their findings will be published in an upcoming issue of Psychological Science, a journal of the Association for Psychological Science.

Existing research has already established that the familiarity component of recognition memory is represented by specific brain activity that can be recorded using electroencephalography (EEG) as early as 300 to 450 milliseconds (ms) after someone is exposed to a familiar object. So Rosburg and his colleagues decided to examine whether this same brain activity is associated with performance on the city-size comparison task, a task that is associated with the recognition heuristic. Participants were presented with pairs of city names and were asked to decide which city in the pair is larger. The authors found that they could indeed predict which city the participant chose based solely on brain activity in the 300-450 ms time window.

By connecting the behavioral processes associated with the recognition heuristic to the brain markers associated with familiarity-based memory, the authors were able to establish that the recognition heuristic really does seem to depend on pure recognition, or familiarity. Rosburg says that this kind of knowledge “allows us to understand both deficient decision making and the benefits of heuristics.”

While the recognition heuristic may allow us to make decisions quickly and efficiently, it may not always lead us down the best path. Rosburg notes that the recognition heuristic may actually be disadvantageous when it comes to picking stocks for our investment portfolios. “For the stock market, there is some reason to believe that the investment returns correlate negatively (and not positively) with the recognition of a company. A lot of companies involved in the credit crunch crisis actually had highly familiar names and this familiarity might have persuaded investors to rely on their products and stocks.”

So is there any way to ensure that we make decisions in which the recognition heuristic works for us and not against us? Rosburg contends that “decision makers will have to learn in which particular environments the feeling of familiarity will guide them to frugal decisions. Only when we, as deciders, realize that some of our choices are related to the feeling of familiarity, we might be able to develop a critical distance to this kind of ‘gut’ feeling.”

Material adapted from Association for Psychological Science.

In a paper published online by Cerebral Cortex, USC researcher Lisa Aziz-Zadeh furthered her ongoing work in mapping out the way the brain generates empathy, even for those who differ physically from themselves.

According to Aziz-Zadeh’s findings, empathy for someone to whom you can directly relate — or example, because they are experiencing pain in a limb that you possess — is mostly generated by the intuitive, sensory-motor parts of the brain. However, empathy for someone to whom you cannot directly relate relies more on the rationalizing part of the brain.

Though they are engaged to differing degrees depending on the circumstance, it appears that both the intuitive and rationalizing parts of the brain work in tandem to create the sensation of empathy, said Aziz-Zadeh, assistant professor at USC’s Division of Occupational Science and Occupational Therapy.

“People do it automatically,” she said.

In an experiment, Aziz-Zadeh and a team from USC showed videos of tasks being performed by hands, feet, and a mouth to a woman who had been born without arms or legs and also to a group of 13 typically developed women. Videos showed activities such as a mouth eating and a hand grasping an object.

Researchers also showed videos of pain, in the form of an injection, being inflicted on parts of the body.

While the participants watched the videos, their brains were scanned using functional magnetic imaging (fMRI), and then those scans were compared, revealing the differing sources of empathy.

In an additional finding, Aziz-Zadeh discovered that when the congenital amputee viewed videos of tasks being performed that she could also perform but using body parts that she did not have, the sensory-motor parts of her brain were still strongly engaged. For example, the participant can hold objects, but uses a stump in conjunction with her chin to do so rather than a hand.

If the goal of the action was impossible for her, then another set of brain regions involved in deductive reasoning were also activated.

Material adapted from University of Southern California.

Results will be published in the October 2011 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.

“Even though adolescents might physically appear grown up, their brains are continuing to significantly develop and mature, particularly in frontal brain regions that are associated with higher-level thoughts, like planning and organization,” said Susan F. Tapert, acting chief of psychology at the VA San Diego Healthcare System as well as professor of psychiatry at the University of California, San Diego. “Heavy alcohol use could interrupt normal brain cell growth during adolescence, particularly in these frontal brain regions, which could interfere with teens’ ability to perform in school and sports, and could have long-lasting effects, even months after the teen uses.”

Tapert, who is also the corresponding author for this study, explained that “working memory” is a term that refers to using and working with information that is held in your mind, such as adding numbers in your head. “Working memory is critical to logical thinking and reasoning,” she said.

Spatial working memory is the ability to perceive the space around you, she added, and then remember and work with this information. “We chose to examine spatial working memory because previous studies have shown it is impaired in adults and adolescents who heavily drink alcohol,” she said. “Deficits on tasks of spatial working memory could relate to difficulties with driving, figural reasoning (like geometry class), sports (remembering and enacting complex plays), using a map, or remembering how to get to places.”

Tapert and her colleagues recruited 95 participants from San Diego-area public schools as part of ongoing longitudinal studies: 40 binge drinking (27 males, 13 females) and 55 control (31 males, 24 females) adolescents 16 to 19 years of age. All of the adolescents completed neuropsychological testing, substance use interviews, and a SWM task during functional magnetic resonance imaging (fMRI).

“Our study found that female teenage heavy drinkers had less brain activation in several brain regions than female non-drinking teens when doing the same spatial task,” said Tapert. “These differences in brain activity were linked to worse performance on other measures of attention and working memory ability. Male binge drinkers showed some but less abnormality as compared to male non-drinkers. This suggests that female teens may be particularly vulnerable to the negative effects of heavy alcohol use.”

“These findings remind us that adolescent boys and girls are biologically different and represent distinctive groups that require separate and parallel study,” noted Edith V. Sullivan, a professor in the department of psychiatry and behavioral sciences at Stanford University School of Medicine. “Adding alcohol to the mix of the developing brain and its multifaceted functions likely complicates the normal developmental trajectory, which is already sexually dimorphic.”

Tapert agreed there is a need to examine gender differences associated with alcohol use, particularly during adolescence, as alcohol seems to have a differential effect on the brain. “Females’ brains develop one to two years earlier than males, so alcohol use during a different developmental stage – despite the same age – could account for the gender differences,” she said. “Hormonal levels and alcohol-induced fluctuations in hormones could also account for the gender differences. Finally, the same amount of alcohol could more negatively affect females since females tend to have slower rates of metabolism, higher body fat ratios, and lower body weight. This is similar to what generally has been found in adult alcoholics: while both men and women are adversely affected, women are often more vulnerable than men to deleterious effects on the brain.”

These findings reflect “relatively normal healthy teens” who engage in social drinking, added Tapert, such as having four to five drinks at a party on the weekend but not using for weeks afterwards. “The teens we examined have relatively limited experience with alcohol, are drinking at levels that are widespread for kids their age – almost a quarter of all seniors admit to binge drinking in the preceding two weeks – have no diagnosable alcohol or drug disorder, do not use other drugs, and do not have any mental health disorders,” said Tapert.

“And yet binge-drinking is a dangerous activity for all youth,” observed Sullivan. “Long after a young person – middle school to college – enjoys acute recovery from a hang-over, this study shows that risk to cognitive and brain functions endures. The effects on the developing brain are only now being identified. ‘Why tamper with normal developmental trajectories that will likely set the stage for cognitive and motor abilities for the rest of one’s life?’”

Material adapted from Alcoholism: Clinical & Experimental Research.

Ayse Pinar Saygin

Now an international team of researchers, led by Ayse Pinar Saygin of the University of California, San Diego, has taken a peek inside the brains of people viewing videos of an uncanny android (compared to videos of a human and a robot-looking robot).

Published in the Oxford University Press journal Social Cognitive and Affective Neuroscience, the functional MRI study suggests that what may be going on is due to a perceptual mismatch between appearance and motion.

'Uncanny valley' refers to an artificial agent's drop in likeability when it becomes too human-like.

Saygin and her colleagues set out to discover if what they call the “action perception system” in the human brain is tuned more to human appearance or human motion, with the general goal, they write, “of identifying the functional properties of brain systems that allow us to understand others’ body movements and actions.”

They tested 20 subjects aged 20 to 36 who had no experience working with robots and had not spent time in Japan, where there is potentially more cultural exposure to and acceptance of androids or even had friends or family from Japan.

Brain response to videos of a robot, android and human. The researchers say they see, in the android condition, evidence of a mismatch between the human-like appearance of the android and its robotic motion. Credit: Courtesy Ayse Saygin, UC San Diego

At the start of the experiment, the subjects were shown each of the videos outside the fMRI scanner and were informed about which was a robot and which human.

The biggest difference in brain response the researchers noticed was during the android condition – in the parietal cortex, on both sides of the brain, specifically in the areas that connect the part of the brain’s visual cortex that processes bodily movements with the section of the motor cortex thought to contain mirror neurons (neurons also known as “monkey-see, monkey-do neurons” or “empathy neurons”).

According to their interpretation of the fMRI results, the researchers say they saw, in essence, evidence of mismatch. The brain “lit up” when the human-like appearance of the android and its robotic motion “didn’t compute.”

“The brain doesn’t seem tuned to care about either biological appearance or biological motion per se,” said Saygin, an assistant professor of cognitive science at UC San Diego and alumna of the same department. “What it seems to be doing is looking for its expectations to be met – for appearance and motion to be congruent.”

In other words, if it looks human and moves likes a human, we are OK with that. If it looks like a robot and acts like a robot, we are OK with that, too; our brains have no difficulty processing the information. The trouble arises when – contrary to a lifetime of expectations – appearance and motion are at odds.

“As human-like artificial agents become more commonplace, perhaps our perceptual systems will be re-tuned to accommodate these new social partners,” the researchers write. “Or perhaps, we will decide it is not a good idea to make them so closely in our image after all.”

Saygin thinks it’s “not so crazy to suggest we brain-test-drive robots or animated characters before spending millions of dollars on their development.”

It is not too practical, though, to do these test-drives in expensive and hard-to-come-by fMRI scanners. So Saygin and her students are currently on the hunt for an analogous EEG signal. EEG technology is cheap enough that the electrode caps are being developed for home use.

Saygin’s coauthors are Thierry Chaminade of Mediterranean Institute for Cognitive Neuroscience, France; Hiroshi Ishiguro of Osaka University and ATR, Japan; Jon Driver of University College London; and Chris Firth of University of Aarhus, Denmark.

The research was funded by the Kavli Institute for Brain and Mind at UC San Diego. Saygin was additionally supported by the California Institute of Telecommunication and Information Technology (Calit2) at UCSD.

Material adapted from University of California – San Diego.

Dr. Stéphane Simon and collaborators in Professor Alan Pegna’s laboratory at Geneva University Hospital, studied a patient brain damaged in an accident who had developed prosopagnosia, or face blindness. They measured her non-conscious responses to familiar faces using different physiological measures of brain activity, including fMRI and EEG. The patient was shown photographs of unknown and famous people, some of whom were famous before the onset of her prosopagnosia (and others who had become famous more recently). Despite the fact that the patient could not recognize any of the famous faces, her brain activity responded to the faces that she would have recognized before the onset of her condition.

“The results of this study demonstrate that implicit processing might continue to occur despite the presence of an apparent impairment in conscious processing,” says Professor Pegna, “The study has also shed light on what is required for our brain to understand what we see around us. Together with other research findings, this study suggests that the collaboration of several cerebral structures in a specific temporal order is necessary for visual awareness to arise.”

Material adapted from Elsevier.

Reference
The article is “When the brain remembers, but the patient doesn’t: Converging fMRI and EEG evidence for covert recognition in a case of prosopagnosia” by Stéphane R. Simon, Asaid Khateb, Alexandra Darque, François Lazeyras, Eugene Mayer, and Alan J. Pegna, and appears in Cortex, Volume 47, Issue 7 (July 2010), published by Elsevier in Italy.

The scientists developed a method with which they can study the neuronal activity in some of the deepest layers of the cortex in rodents, something that has not been possible up until now.

The cerebral cortex, or just cortex, is the outermost sheet of neural tissue of the mammalian brain. It plays a key role in memory, perceptual awareness, and consciousness. It receives and processes the information from the senses, such as sight, touch, or smell. The principles underlying these processes are not fully understood yet.

Jason Kerr, research group leader of the Network Imaging Group at the Max Planck Institute for Biological Cybernetics in Tübingen and his colleagues from the same institute, Wolfgang Mittmann, Damian Wallace, and Uwe Czubayko managed to image neuronal activity simultaneously from many neurons with single cell resolution, over twice as deep as previously achieved.

In collaboration with Winfried Denk from the Department Biomedical Optics at the Max Planck Institute for Medical Research in Heidelberg and scientists from the Howard Hughes Medical Institute in Ashburn, Virginia, they studied the neural cell activity in layer L5b in the adult rodent, which, as well as being one of the output layers of the cortex, it is also only one layer away from the cortex end.

Up until now. most imaging studies were restricted to the upper third of the cortex in the so-called layers L2 and L3. Deeper layers could only be studied using electrodes or by damaging the cortex using optical fibers or prisms. The Max Planck scientists now further developed a method with which they can see exactly which cell is active and, importantly, what cells are not active during a stimulus up to one millimeter from the cortical surface. This has enabled the scientists to measure the spatiotemporal organization of activity in these deep layers.

“We express a genetically encoded fluorescent activity reporter in the neurons of interest and with this we can measure the activity of many neurons at the same time,” explains Jason Kerr.

Left is an image of a cross-section through the whole mammalian brain that shows both brain hemispheres (solid white outline) as well as the overlaying cerebral cortex which is made up of many layers (I -VI). On the right hemisphere are brain cells, neurons, labeled with a genetically encoded fluorescent marker that reports back the cells activity by fast changes in brightness. This image has been taken from a brain slice post mortem where the lower limit of the cortex can be seen (dotted white line). Right, this image shows the same deep layer V brain cells (red box) labeled with the genetically encoded fluorescent marker but actually imaged non-invasively from a living animal using a modified multiphoton microscope, or RAMM approach. This allows scientists to study activity in neuronal populations deep in the cortex of an awake behaving animal & will lead to a deeper understanding of how cortical networks perform computations. ©: W. Mittmann, J. Kerr / MPI for Biological Cybernetics (click to enlarge)

Changes in brightness of the fluorescent marker are relative to the activity of the neuron. Using the new multi photon imaging technique the activity of many neuronal populations in the deeper cortical layers can be recorded simultaneously in vivo. Jason Kerr and his team combined regenerative amplification multiphoton microscopy (RAMM) with generally encoded calcium indicators to extend multi photon imaging of neuronal population activity to the deeper layers of the cortex. Using this approach, they found, that it could be used to record and quantify spontaneous and activity evoked in the animal by sensory stimulation such as whisker touches or natural movies in neuronal populations of the layer L5a and L5b.

The goal of their research is to record activity from populations of neurons located in all cortical layers including from the layer 6 to layer 1. In combination with genetically encoded activity indicators, the team plans to investigate the spatial temporal organization of neuronal activity from all cortical layers in animals trained to discriminate between objects.

Further, they want to address the question of whether the deeper layers also show spatiotemporal re-organization similar to that shown for the upper cortical layers during learning. With these technical advances the scientists aim to gain insights into cortical circuits involved in decision making in the awake, behaving cortex, and how these circuits are functionally modified during learning.

Material adapted from Max-Planck-Gesellschaft.

Dr. Michael Spencer, who led the study from the University’s Autism Research Centre, said: “The findings provide a springboard to investigate what specific genes are associated with this biomarker. The brain’s response to facial emotion could be a fundamental building block in causing autism and its associated difficulties.”

Previous research has found that people with autism often struggle to read people’s emotions and that their brains process emotional facial expressions differently to people without autism. However, this is the first time scientists have found siblings of individuals with autism have a similar reduction in brain activity when viewing others’ emotions.

In one of the largest functional MRI (fMRI) studies of autism ever conducted, the researchers studied 40 families who had both a teenager with autism and a sibling without autism. Additionally, they recruited 40 teenagers with no family history of autism. The 120 participants were given fMRI scans while viewing a series of photographs of faces which were either neutral or expressing an emotion such as happiness. By comparing the brain’s activity when viewing a happy verses a neutral face, the scientists were able to observe the areas within the brain that respond to this emotion.

Despite the fact that the siblings of those with autism did not have a diagnosis of autism or Asperger syndrome, they had decreased activity in various areas of the brain (including those associated with empathy, understanding others’ emotions and processing information from faces) compared to those with no family history of autism. The scans of those with autism revealed that the same areas of the brain as their siblings were also underactive, but to a greater degree. (These brain regions included the temporal poles, the superior temporal sulcus, the superior frontal gyrus, the dorsomedial prefrontal cortex and the fusiform face area.)

Because the siblings without autism and the controls differed only in terms of the siblings having a family history of autism, the brain activity differences can be attributed to the same genes that give the sibling their genetic risk for autism.

Explaining why only one of the siblings might develop autism when both have the same biomarker, Dr Spencer said: “It is likely that in the sibling who develops autism additional as yet unknown steps – such as further genetic, brain structure or function differences – take place to cause autism.”

It is known that in a family where one child already has autism, the chances of a subsequent child developing autism are at least 20 times higher than in the general population. The reason for the enhanced risk, and the reason why two siblings can be so differently affected, are key unresolved questions in the field of autism research, and Dr Spencer’s group’s findings begin to shed light on these fundamental questions.

Professor Chris Kennard, chairman of the Medical Research Council funding board for the research, said: “This is the first time that a brain response to different human facial emotions has been shown to have similarities in people with autism and their unaffected brothers and sisters. Innovative research like this improves our fundamental understanding of how autism is passed through generations affecting some and not others. This is an important contribution to the Medical Research Council’s strategy to use sophisticated techniques to uncover underpinning brain processes, to understand predispositions for disease, and to target treatments to the subtypes of complex disorders such as autism.”

Material adapted from University of Cambridge.

Reference
The paper “A novel functional brain imaging endophenotype of autism: the neural response to facial expression of emotion,” is scheduled for publication in the July issue of Translational Psychiatry.

Waldhauser’s tests are carried out in a laboratory environment where volunteers are asked to practice forgetting, or attempting to forget facts. Through EEG measurements, Waldhauser shows that the same parts of the brain are activated when we restrain a motor impulse and when we suppress a memory. And just as we can practice restraining motor impulses, we can also train ourselves to repress memories (i.e., to forget).

Waldhauser points out several situations in which forgetting could be helpful. People suffering from depression often dwell on negative thoughts which might best be repressed or forgotten in order for the individual to emerge from the depression. The same thing goes for people with post-traumatic stress disorder; the trauma makes it difficult for the affected person to act rationally and to resolve his or her situation. But the possible consequences of a deliberate repression of memories are still not clearly established.

“We know that ‘forgotten’ or repressed feelings often manifest themselves as physiological reactions”, says Waldhauser, who is careful to point out that the volunteers were trained to forget neutral information in a controlled laboratory environment. Training to forget a traumatic event would be more complex.

Waldhauser has not only shown that we can deliberately forget things. Through EEG measurements, he has also managed to capture the exact moment when the memory is inhibited, that is when the forgetfulness is imposed.

The inhibition of memory eases off after a few hours. But the more often information is suppressed, the more difficult it becomes to retrieve it, as Waldhauser has shown through studies in a laboratory environment.

“If the memories have been suppressed over a long period of time, they could be extremely difficult to retrieve”, says Waldhauser.

Gerd Thomas Waldhauser has publicly defended his doctoral thesis, “Behavioral and Electrophysiological Correlates of Inhibition in Episodic Memory.”

Material adapted from Lund University .

A new study by researchers at Beth Israel Deaconess Medical Center (BIDMC) suggests that specific brain areas actively orchestrate competition between memories, and that by disrupting targeted brain areas through transcranial magnetic stimulation (TMS), you can preserve memory – and prevent forgetting.

The findings are described in the June 26 Advance On-line issue of Nature Neuroscience.

“For the last 100 years, it has been appreciated that trying to learn facts and skills in quick succession can be a frustrating exercise,” explains Edwin Robertson, MD, DPhil, an Associate Professor of Neurology at Harvard Medical School and BIDMC. “Because no sooner has a new memory been acquired than its retention is jeopardized by learning another fact or skill.”

Robertson, together with BIDMC neurologist and coauthor Daniel Cohen, MD, studied a group of 120 college-age students who performed two concurrent memory tests. The first involved a finger-tapping motor skills task, the second a declarative memory task in which participants memorized a series of words. (Half of the group performed the tasks in this order, while a second group learned these same two tasks in reverse order.)

“The study subjects performed these back-to-back exercises in the morning,” he explains. “They then returned 12 hours later and re-performed the tests. As predicted, their recall for either the word list or the motor-skill task had decreased when they were re-tested.”

In the second part of the study, Robertson and Cohen administered TMS following the initial testing. TMS is a noninvasive technique that uses a magnetic simulator to generate a magnetic field that can create a flow of current in the brain.

“Because brain cells communicate through a process of chemical and electrical signals, applying a mild electrical current to the brain can influence the signals,” Robertson explains. In this case, the researchers targeted two specific brain regions, the dorsolateral prefrontal cortex and the primary motor cortex. They discovered that by applying TMS to specific brain areas, they were able to reduce the interference and competition between the motor skill and word-list tasks and both memories remained intact.

“This elegant study provides fundamental new insights into the way our brain copes with the challenge of learning multiple skills and making multiple memories,” says Alvaro Pascual-Leone, MD, PhD, Director of the Berenson-Allen Center for Noninvasive Brain Stimulation at BIDMC. “Specific brain structures seem to carefully balance how much we retain and how much we forget. Learning and remembering is a dynamic process and our brain devotes resources to keep the process flexible. By better understanding this process, we may be able to find novel approaches to help enhance learning and treat patients with memory problems and learning disabilities.”

“Our observations suggest that distinct mechanisms support the communication between different types of memory processing,” adds Robertson. “This provides a more dynamic and flexible account of memory organization than was previously believed. We’ve demonstrated that the interference between memories is actively mediated by brain areas and so may serve an important function that has previously been overlooked.”

Material adapted from Beth Israel Deaconess Medical Center .

Researcher Nikolaus F. Troje

But what role does motion play in that process? Does the visual system use it only to connect the dots to create a coherent, or “global,” structure? Troje and his colleagues — Masahiro Hirai and Daniel R. Saunders at Queen’s, and Dorita H. F. Chang, now at the University of Birmingham, UK — investigated this question in a new study, to be published in an upcoming issue of Psychological Science, a journal of the Association for Psychological Science.

They presented their participants with computer-generated stimuli showing 11 light points representing the shoulder, hip, elbows, wrists, knees, and ankles of a person walking as on a treadmill. After a two-second display, the observers had to indicate which direction they believed the walker was facing.

This is an easy task, and the participants performed it almost without fail — even though the point-light walker was masked with 100 randomly placed additional dots. But they were also able to do it if the global structure of the body was entirely disrupted by randomly scrambling the 11 dots. “The local motion of individual dots contained enough information about the walker’s facing direction,” says Troje.

But when the whole thing was turned upside-down, the participants could no longer discern which way the figure was walking. Why? Says Troje: “The visual system uses the information contained in these local dot movements — mainly the ones of the feet — only when it is validated by additional properties that do not in themselves carry any information about facing direction”—in this case the proper vertical orientation, feet on the bottom, head on top.

An observer can not tell the facing direction of a stationary upright figure. But put the local motion together with an upright position, even mix up and mask all the light points. And “direction discrimination of these ‘scrambled’ walkers is almost as good as with structurally coherent walkers,” Troje says.

Why is the visual system so acute even when the shape of a figure is totally broken down? To survive, we have to be able “to detect the presence of a living being in the visual environment regardless of whether it is a fellow human, a potentially dangerous predator, or even a prey animal,” says Troje. “For that purpose, we need a detection mechanism that is independent of the particular shape of an animal.”

Parsing these effects can help us understand — and appreciate — our extraordinary perceptual assets. “It tells us how sophisticated our visual system is in using information about the structure, the physics, and the regularities of the visual world,” he says.

Material adapted from Association for Psychological Science .