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SUMMARY:Flexible mental computations through regulation of cortical dynami
 cs - Mehrdad Jazayeri
DTSTART:20180424T120000Z
DTEND:20180424T130000Z
UID:TALK105025@talks.cam.ac.uk
CONTACT:John Mollon
DESCRIPTION:Mental computations can be flexibly adjusted according to inte
 rnal beliefs\, contextual cues\, sensory evidence\, and desired outcomes. 
 The mechanisms supporting this flexibility are not understood. In this tal
 k\, I will describe how cortical circuits support this flexibility during 
 1) motor planning\, 2) mental transformation\, and 3) Bayesian inference. 
 Using a combination of task design\, neurophysiology\, and recurrent neura
 l network modeling\, we have found that the underlying computational princ
 iples can be gleaned from the structure and dynamics of population cortica
 l activity. For example\, to produce different time intervals\, cortical c
 ircuits establish an internal model that inverts the desired interval to a
 n appropriate speed command for driving population neural activity toward 
 an action-triggering state. Flexible mental transformations are in turn su
 pported by inputs and initial conditions that systematically control the b
 ehavior of cortical internal models. Finally\, Bayesian inference is made 
 possible by integrating inputs within a cortical network whose latent dyna
 mics encode prior beliefs. I will use these results to introduce a novel a
 nd potentially general computation-through-dynamics (CTD) framework for un
 derstanding behaviorally relevant computations in terms of cortical dynami
 cs. According to CTD\, cortical networks establish a structured reservoir 
 of latent dynamics capable of performing a variety of computations. Inputs
  and initial conditions exploit this substrate to rapidly and flexibly rec
 onfigure the system to perform different mental computations. I will concl
 ude by highlighting the strengths and limitations of CTD as a parsimonious
  framework for linking brain to behavior.
LOCATION:Kenneth Craik Room\, Craik-Marshall Building\, Downing Site
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