BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Optimality among optimals: decision making from neurobiological 
 ‘noisy’ signals within the cortico-basal-ganglia system - Javier A. Ca
 ballero\, Adaptive Behaviour Research Group\, Department of Psychology\, T
 he University of Sheffield
DTSTART:20100921T150000Z
DTEND:20100921T160000Z
UID:TALK26028@talks.cam.ac.uk
CONTACT:Prof Máté Lengyel
DESCRIPTION:The basal ganglia\, a group of sub-cortical nuclei\, have been
  implicated in decision making in a variety of contexts ranging from senso
 ry-motor functions to working memory\, learning and emotions (Redgrave et 
 al\, 1999). Recently the cortico-basal-ganglia system (CBGS) has been prop
 osed to be performing such allocation of resources in an optimal fashion (
 Bogacz & Gurney\, 2007)\, through a quasi-Bayesian algorithm known as mult
 i-hypothesis sequential probability ratio test (MSPRT). Hitherto\, decisio
 n making models\, including that used by Bogacz & Gurney\, have typically 
 considered inputs with Gaussian (allowing negative going signals) or discr
 ete distributed noise (e.g. Poisson). However\, we know that neurobiologic
 al signals are continuously distributed and always take positive values. T
 o address this problem we have shown how the MSPRT and CBGS may accommodat
 e non-Gaussian continuous distributions that better describe the neural da
 ta. We showed that\, all provided with the same conditions\, our MSPRTs re
 duce the sample size required to reach a decision\, by at least one order 
 of magnitude\, compared to the best previous published model. This as the 
 computational side of it\, however we also showed that these new models do
  so while reproducing the trends in the neurobiological recordings availab
 le and preserving their mapping onto the CBGS. In this talk I will explain
  the development of our project\, the results and where we are heading now
 .\n
LOCATION:Cambridge University Engineering Department\, Rm BE4-38 (http://l
 earning.eng.cam.ac.uk/Public/Directions)
END:VEVENT
END:VCALENDAR