Hansem Sohn, Ph.D.
October 28(Thu) - October 28(Thu), 2021
12PM
ZOOM (ID: 728-142-6028)
Neuro@noon Seminar
Date: 12PM, Thursday, October 28th
ZOOM 회의 참가 ID: 728-142-6028
Speaker: Hansem Sohn, Ph.D.
(Department of Brain & Cognitive Sciences, MIT)
Title: Neural computations underlying Bayesian timing behaviors
Abstract:
Statistical regularities in the environment create prior beliefs that we rely on to optimize our behavior when sensory information is uncertain. Bayesian theory formalizes how prior beliefs can be leveraged and has had a major impact on models of perception, sensorimotor function, and cognition. However, it is not known whether and how the brain implements Bayesian computations. Using time perception as a case study, I will tackle this question from two facets. First, I will present a neural mechanism for encoding Bayesian time estimates through warping of neural population dynamics in the macaque medial frontal cortex. These results provide a general neural mechanism for how prior beliefs can be used to mitigate the effect of sensory uncertainty. In the second part of the talk, I will describe a novel experimental paradigm that provides a way to adjudicate whether and when humans rely on internal models of priors (past sensory experiences) and cost functions (decision outcomes). Our approach probes sensitivity of humans to transitions between prior-cost pairs that demand the same optimal policy (metamers) but distinct internal models. We demonstrate the utility of our approach in two experiments that were classically explained by Bayesian theory. We hope this work will provide a path toward resolving the controversies surrounding the notion of the Bayesian brain.