High-resolution, flexible, active electrode array.
(photo credit: Travis Ross and Yun Soung Kim, University of Illin)
Newswise — PHILADELPHIA - 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.
Composed of 720 silicon nanomembrane transistors in a multiplexed
360-channel array, the newly designed ultrathin, flexible, foldable
device can be positioned not only on the brain surface but also inside
sulci and fissures or even between the cortical hemispheres, areas that
are physically inaccessible to conventional rigid electrode arrays.
Current arrays also require separate wires for each individual sensor,
meaning that they can sample broad regions of the brain with low
resolution or small regions with high resolution, but not both. The
multiplexed nanosensors of the new device can cover a much large brain
area with high resolution, while using almost ten times fewer wires.
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 observation of spiral wave activity also served to highlight the
extreme sensitivity and resolving capacity of this new active array,
which was able to easily distinguish normal signal patterns from
abnormal waves even in the same frequency ranges. The activity recorded
by Litt’s research team has enormous implications not only for
controlling seizures but for understanding and treating disorders of
other brain processes affecting sleep, memory, and learning, and for the
characterizing and treating chronic pain, depression, and other
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.This article was first published at www.newswise.com