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SUMMARY:Evaluating dynamical systems hypotheses for pattern generation in 
 motor cortex - Lea Duncker\, Columbia
DTSTART:20250107T150000Z
DTEND:20250107T163000Z
UID:TALK225859@talks.cam.ac.uk
CONTACT:Daniel Kornai
DESCRIPTION:The rich repertoire of skilled mammalian behavior is the produ
 ct of neural circuits that generate robust and flexible patterns of activi
 ty distributed across populations of neurons. Decades of associative studi
 es have linked many behaviors to specific patterns of population activity\
 , but association alone cannot reveal the dynamical mechanisms that shape 
 those patterns. Are local neural circuits high-dimensional dynamical reser
 voirs able to generate arbitrary superpositions of patterns with appropria
 te excitation? Or might circuit dynamics be shaped in response to behavior
 al context so as to generate only the low-dimensional patterns needed for 
 the task at hand? Here\, we address these questions within primate motor c
 ortex by delivering optogenetic and electrical microstimulation perturbati
 ons during reaching behavior. We develop a novel analytic approach that re
 lates measured activity to theoretically tractable\, dynamical models of e
 xcitatory and inhibitory neurons. Our computational modeling framework all
 ows us to quantitatively evaluate different hypotheses about the dynamical
  mechanisms underlying pattern generation against perturbation responses. 
 Our results demonstrate that motor cortical activity during reaching is sh
 aped by a self-contained\, low-dimensional dynamical system. The subspace 
 containing task-relevant dynamics proves to be oriented so as to be robust
  to strong non-normal amplification within cortical circuits. This task dy
 namics space exhibits a privileged causal relationship with behavior\, in 
 that stimulation in motor cortex perturbs reach kinematics only to the ext
 ent that it alters neural states within this subspace. Our results resolve
  long-standing questions about the dynamical structure of cortical activit
 y associated with movement\, and illuminate the dynamical perturbation exp
 eriments needed to understand how neural circuits throughout the brain gen
 erate complex behavior.
LOCATION:CBL Seminar Room\, Engineering Department\, 4th floor Baker build
 ing
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