BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Memento EPFL// BEGIN:VEVENT SUMMARY:Brain-machine interfaces\, microstimulation\, and movement primiti ves DTSTART:20140603T100000 DTEND:20140603T110000 DTSTAMP:20260407T211043Z UID:4169580576a80645a02872a9d896b7521115ab5694a91606e9ed831c CATEGORIES:Conferences - Seminars DESCRIPTION:Dr Simon Overduin\, University of California\, Berkeley USA\n Brain-machine interfaces (BMIs) offer the potential to recover movement pl ans from the brains of paralyzed individuals. Work over th¬e past few yea rs has successfully used motor cortical activity to control computer curso rs\, robots\, or muscle stimulators of up to a handful of independent dime nsions. These demonstrations typically involve non-paralyzed\, non-human a nimal models such as rhesus macaques. Translation of this work to human pa tients presents several major challenges\, many of them intrinsic to the n ature of intact animal models. For instance\, decoders tested in non-paral yzed subjects typically rely on overt (rather than covert) movement contro l\, intact (rather than interrupted) sensations\, and (at most) short-term neural adaptation to the decoder. My work with neuroimaging and transcran ial magnetic stimulation of human motor cortex highlights each of these li mitations. However\, the focus of my talk will be on limitations in the ar chitecture of neuroprosthetic decoders themselves. As commonly tested in a nimal models\, these decoders implicitly assume that motor control is upda ted moment-by-moment\, concerned with extrinsic movement variables (such a s Cartesian hand speed)\, and scalable to arbitrarily many dimensions. Yet in biological movement control\, the nervous system arguably uses “moto r primitives” to reduce the frequency at which commands are issued to gr oups of muscles acting in concert. Such primitives can be causally demonst rated by intracortical microstimulation of motor cortex. In macaques\, mic rostimulation-evoked forelimb movements have smooth speed profiles charact eristic of intermittent submovements seen in natural behaviors. The micros timulation-evoked forces tend to drive the arm towards invariant postures in the workspace around the animal. Across stimulation sites\, the underly ing muscle activations are reducible to linear sums of a few basic pattern s\, each corresponding to a muscle synergy evident in natural movements. I argue that the brain—and potentially BMIs—can simplify motor planning by exploiting these properties of primitives: intermittent planning\, pos tural equivalence\, and low dimensionality.\nBio:\nDr.  Overduin is a pos tdoctoral researcher working in the areas of motor control and neuroprosth etics\, with Dr. Jose Carmena in the Department of Electrical Engineering and Computer Sciences at UC Berkeley. He received his PhD in Systems Neuro science from MIT following studies of motor control and learning with Dr. Emilio Bizzi\, and a BSc in Biology and Psychology from Wilfrid Laurier Un iversity in Canada. In his research\, Dr. Overduin has aimed to understand and resolve some basic controversies in motor control and learning\, incl uding the necessity of primary motor cortex in early sensorimotor adaptati on\, the existence of motor consolidation in later sensorimotor learning\, and the neurophysiological distinction between sensorimotor adaptation an d sequence learning\, as well as that between overt and covert movement. H is current work involves translating the results of his neurophysiological studies into new experimental models and neuroprosthetic decoders for mov ement disorders including dystonia and spinal cord injury. Dr. Overduin ha s won fellowships and grants from numerous public and private research age ncies in Canada and the US\, including NSERC and CIHR in Canada\, and the American Heart Association\, Dystonia Medical Research Foundation\, and NS F in the US. LOCATION:SV1717a http://plan.epfl.ch/?room=SV%201717A STATUS:CONFIRMED END:VEVENT END:VCALENDAR