A team of researchers co-led by the University of Pennsylvania has developed and tested a new high-resolution, ultra-thin device capable of recording brain activity from the cortical surface without having to use penetrating electrodes. The device could make possible a whole new generation of brain-computer interfaces for treating neurological and psychiatric illness and research. The work was published in Nature Neuroscience.
“The new technology we have created can conform to the brain’s unique geometry, and records and maps activity at resolutions that have not been possible before,” says Brian Litt, MD, the study’s senior author and Associate Professor of Neurology at the Perelman School of Medicine and Bioengineering at the University of Pennsylvania. “Using this device, we can explore the brain networks underlying normal function and disease with much more precision, and its likely to change our understanding of memory, vision, hearing and many other normal functions and diseases.” For our patients, implantable brain devices could be inserted in less invasive operations and, by mapping circuits involved in epilepsy, paralysis, depression and other ‘network brain disorders’ in sufficient detail, this could allow us to intervene to make patients better, Litt said.

High-resolution, flexible, active electrode array with 360 amplified and multiplexed electrodes. Only 39 wires are needed to sample from all of the 360 electrodes simultaneously. The electrode array is ultrathin and flexible, allowing close contact with the brain and high-resolution recordings of seizures. Credit: Travis Ross and Yun Soung Kim, University of Illinois at Urbana-Champaign (click to enlarge)
Monitoring and studying the brain’s constant electrical activity, or to alter it when it goes awry, often requires the placement of electrodes deep within specific regions of the brain. These currently used devices can be clumsy and of low resolution, and those used for neuromotor prostheses can cause tissue inflammation and hemorrhages.
Study collaborators including lead author Jonathan Viventi, PhD, an assistant professor at the Polytechnic Institute of New York University who worked with Litt on the project as a postdoctoral fellow at Penn, and colleagues John Rogers from the University of Illinois Urbana-Champaign, and Dae-Hyeong Kim from Seoul National University, worked together to conceive and build the array, believed to be the first device of its kind to be used as a brain interface.
In animal models, researchers observed responses to visual stimuli and recorded previously unknown details of sleep patterns and brain activity during epileptic seizures. The array recorded spiral waves during seizure activity that have not been previously recorded in whole brain. These patterns are similar to those seen in the heart during ventricular fibrillation, raising the possibility of fighting epilepsy with some of the same methods used to treat cardiac arrhythmias, like focal destruction or ablation of abnormal circuits.

The extreme flexibility of the device allowed it to be folded in half without damage, forming a unique double-sided recording device. This device can be used to interface with rarely explored brain regions, such as the interior of sulci and in-between the brain hemispheres. Credit: Yun Soung Kim, University of Illinois at Urbana-Champaign (click to enlarge)
Ultimately, the researchers expect that flexible electrode arrays can be perfected for use for various therapeutic and research purposes throughout the body. They could serve as neuroprostheses, pacemakers, ablative devices, or neuromuscular stimulators. Their versatility, sensitivity, and reduced effect on surrounding tissues puts them in the forefront of the next generation of brain-computer interfaces.
In addition to the National Institutes of Health’s National Institute of Neurological Disorders and Stroke (NINDS), the research was supported by the National Science Foundation, the Division of Materials Sciences at the U.S. Department of Energy, Citizens United for Research in Epilepsy, the Dr. Michel and Mrs. Anna Mirowski Discovery Fund for Epilepsy Research, and NIH’s National Heart, Lung, and Blood Institute.
Material adapted from Penn Medicine.
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