BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:TODAY Adrian Seminar: "\;Starting new actions and learning fro m it"\; - Rui Costa\, Zuckerman Institute\, Columbia DTSTART:20180212T163000Z DTEND:20180212T180000Z UID:TALK99187@talks.cam.ac.uk CONTACT:Lyn Dakin DESCRIPTION:The ability of animals to build individual repertoires based o n the consequences of their actions is fascinating\, and essential for sur vival. Understanding this process\, i.e. how actions are learned through t rial and feedback\, requires mechanistic insight into how self-paced actio ns are initiated\, how they can be selected/initiated again\, and how feed back can shape their execution and organization. We use behavioral\, genet ic\, electrophysiological\, and optical approaches to gain this mechanisti c insight. The combination of these approaches allowed us to uncover that dopaminergic neurons are transiently active before self-paced movement ini tiation. This activity is not action-specific and modulates both the proba bility of initiation and the vigor of future movements\, but does not affe ct ongoing movement. Dopamine is supposed to have opposite effects on down stream striatal direct and indirect pathways. Contrary to what is classica lly postulated\, we found that both striatal direct and indirect pathways are active during movement initiation. The activity in both pathways is ac tion-specific\, is organized into specific spatiotemporal patterns\, and h as complementary but different roles in movement initiation. Furthermore\, when animals organize their individual movements in sequences or chunks\, activity related to the initiation or termination of these chunks emerges in dopaminergic and striatal circuits. The behavioral and neuronal re-org anization that accompanies sequence learning requires plasticity between t he cortex and striatum. Finally\, using operant tasks and closed-loop brai n machine paradigms\, we revealed that cortico-striatal plasticity is nece ssary to select\, reinforce and shape the specific neural and behavioral p atterns that lead to desirable outcomes. These data invite new models on t he mechanisms underlying self-paced movement initiation\, and motor dysfun ction in Parkinson’s disease. They also suggest that cortico-basal gangl ia circuits play a generic role in learning to produce task-relevant neura l activity and behavioral patterns.\n\n LOCATION:The Hodgkin Huxley Seminar Room\, Department of Physiology Develo pment and Neuroscience END:VEVENT END:VCALENDAR