Why motor cortex responses don’t obey expectations

ECE Seminar: Why motor cortex responses don’t obey expectations

Starts at: March 22, 2018 4:30 PM

Ends at: 6:00 PM

Speaker: Dr. Mark Churchland

Affiliation: Columbia University

Refreshments provided: Yes

Link to Abstract

Link to Video (1)


A central question in motor physiology has been whether motor cortex activity resembles muscle activity, and if not, why not? Over fifty years, extensive observations have failed to provide a concise answer, and the topic remains much debated. To provide a different perspective, we employed a novel behavioral paradigm that affords extensive comparison between time-evolving neural and muscle activity. Single motor-cortex neurons displayed many muscle-like properties, but the structure of population activity was not muscle-like. Unlike muscle activity, neural activity was structured to avoid ‘tangling’: moments where similar activity patterns led to dissimilar future patterns. Avoidance of tangling was present across tasks and species. Network models revealed a potential reason for this consistent feature: low tangling confers noise robustness. Remarkably, we were able to predict motor cortex activity from muscle activity alone, by leveraging the hypothesis that muscle-like commands are embedded in additional structure that yields low tangling. Our results argue that motor cortex embeds descending commands in additional structure that ensure low tangling, and thus noise-robustness. The dominant structure in motor cortex may thus serve not a representational function (encoding specific variables) but a computational function: ensuring that outgoing commands can be generated reliably.

Professor Churchland is an Assistant Professor in the Department of Neuroscience at Columbia University Medical Center. He is the co-director of the Grossman Center for the Statistics of Mind. He received his BA in mathematics and psychology from Reed College in Portland Oregon. He received his PhD in neuroscience from the University of California San Francisco. His postdoctoral work was in the Neural Prosthetic Systems Laboratory at Stanford University. Professor Churchland’s laboratory focuses on how the brain controls voluntary movement.

Professor Churchland is a recipient of the 2012 NIH Directors’ New Innovator Award. He received a 2015 Klingenstein-Simons Fellowship Award, a 2013 McKnight Scholar Award, a 2013 Sloan Research Fellowship, and a 2012 Searle Scholars Award. He was a 2006 recipient of the Burroughs Wellcome Fund Career Award and a 2003 recipient of the Helen Hay Whitney Research Fellowship.