Citation

Thura D, Beauregard-Racine J, Fradet CW, Cisek P. J. Neurophysiol. 2012; 108(11): 2912-2930.

Affiliation

Univ. de Montreal.

Copyright

(Copyright © 2012, American Physiological Society)

DOI

10.1152/jn.01071.2011

PMID

22993260

Abstract

It is often suggested that decisions are made when accumulated sensory information reaches a fixed accuracy criterion. This is supported by many studies showing gradual build-up of neural activity to a threshold. However, the proposal that this build-up is caused by sensory accumulation is challenged by findings that decisions are based on information from a time window much shorter than the build-up process. Here, we propose that in natural conditions where the environment can suddenly change, the policy that maximizes reward rate is to estimate evidence by accumulating only novel information and then compare the result to a decreasing accuracy criterion. We suggest the brain approximates this policy by multiplying an estimate of sensory evidence with a motor-related urgency signal, and that the latter is primarily responsible for neural activity build-up. We support this hypothesis using human behavioral data from a modified random-dot motion task in which motion coherence is changing during each trial.

Language: en