RT Journal Article
SR Electronic
T1 Lapses in perceptual judgments reflect exploration
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 613828
DO 10.1101/613828
A1 Sashank Pisupati
A1 Lital Chartarifsky-Lynn
A1 Anup Khanal
A1 Anne K. Churchland
YR 2019
UL http://biorxiv.org/content/early/2019/04/19/613828.abstract
AB During perceptual decision making, subjects often display a constant rate of errors independent of evidence strength, referred to as “lapses”. Their proper treatment is crucial for accurate estimation of perceptual parameters, however they are often treated as a nuisance arising from motor errors or inattention. Here, we propose that lapses can instead reflect a dynamic form of exploration. We demonstrate that perceptual uncertainty modulates the probability of lapses both across and within modalities on a multisensory discrimination task in rats. These effects cannot be accounted for by inattention or motor error, however they are concisely explained by uncertainty-guided exploration. We confirm the predictions of the exploration model by showing that changing the magnitude or probability of reward associated with one of the decisions selectively affects the lapses associated with that decision in uncertain conditions, while leaving “sure-bet” decisions unchanged, as predicted by the model. Finally, we demonstrate that muscimol inactivations of secondary motor cortex and posterior striatum affect lapses asymmetrically across modalities. The inactivations can be captured by a devaluation of actions corresponding to the inactivated side, and do not affect “sure-bet” decisions. Together, our results suggest that far from being a nuisance, lapses are informative about subjects’ action values and deficits thereof during perceptual decisions.