Interpreting Primary Motor Cortex Function based on Optimal Feedback Control

Stephen Scott
Department of Anatomy and Cell Biology, Queen's University

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     Last modified: April 28, 2007
     Presentation date: 08/11/2007 2:40 PM in MCC
     (View Schedule)

Abstract
Primary motor cortex (MI) is a key component of the volitional motor system providing the largest contribution to the corticospinal tract and receiving input from many cortical and subcortical structures. The most common approach for interpreting MI function has been based on the notion of sensorimotor transformations, focusing attention on experiments that identify which coordinate frame best describes neural activity in MI. However, myriad coordinate frames or neural representations have been observed illustrating correlations with spatial goals, hand motion, joint motion, muscular torque, muscular power and EMG activity. How all these
?representations? contribute or create coordinated motor behavior remains unclear. The focus of my talk will be to provide an alternate approach for interpreting MI function based on optimal feedback control. This approach re-emphasizes the importance of sensory feedback to MI function and the adaptive nature of long-latency reflexes that predominantly involve a transcortical pathway through MI. I will describe experiments that examine the highly adaptive nature of long-latency reflexes in humans either to maintain online control or to rapidly switch behavioral goals. I hope to present preliminary observations illustrating corresponding rapid context-dependent changes in the response of MI neurons of non-human primates for these same tasks.