BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Computational Neuroscience Journal Club - James Heald (CBL)
DTSTART:20170418T150000Z
DTEND:20170418T160000Z
UID:TALK72157@talks.cam.ac.uk
CONTACT:Daniel McNamee
DESCRIPTION:James Heald will cover:\n\n* Cerebellar granule cells encode t
 he expectation of reward\n* Mark J. Wagner\, Tony Hyun Kim\, Joan Savall\,
  Mark J. Schnitzer\, Liqun Luo\n* Nature (April 2017)\n* http://www.nature
 .com/nature/journal/v544/n7648/full/nature21726.html\n\nAbstract:\nThe hum
 an brain contains approximately 60 billion cerebellar granule cells1\, whi
 ch outnumber all other brain neurons combined. Classical theories posit th
 at a large\, diverse population of granule cells allows for highly detaile
 d representations of sensorimotor context\, enabling downstream Purkinje c
 ells to sense fine contextual changes2\, 3\, 4\, 5\, 6. Although evidence 
 suggests a role for the cerebellum in cognition7\, 8\, 9\, 10\, granule ce
 lls are known to encode only sensory11\, 12\, 13 and motor14 context. Here
 \, using two-photon calcium imaging in behaving mice\, we show that granul
 e cells convey information about the expectation of reward. Mice initiated
  voluntary forelimb movements for delayed sugar-water reward. Some granule
  cells responded preferentially to reward or reward omission\, whereas oth
 ers selectively encoded reward anticipation. Reward responses were not res
 tricted to forelimb movement\, as a Pavlovian task evoked similar response
 s. Compared to predictable rewards\, unexpected rewards elicited markedly 
 different granule cell activity despite identical stimuli and licking resp
 onses. In both tasks\, reward signals were widespread throughout multiple 
 cerebellar lobules. Tracking the same granule cells over several days of l
 earning revealed that cells with reward-anticipating responses emerged fro
 m those that responded at the start of learning to reward delivery\, where
 as reward-omission responses grew stronger as learning progressed. The dis
 covery of predictive\, non-sensorimotor encoding in granule cells is a maj
 or departure from the current understanding of these neurons and markedly 
 enriches the contextual information available to postsynaptic Purkinje cel
 ls\, with important implications for cognitive processing in the cerebellu
 m.
LOCATION:Cambridge University Engineering Department\, CBL\, BE-438 (http:
 //learning.eng.cam.ac.uk/Public/Directions)
END:VEVENT
END:VCALENDAR