Neuronal Learning of Invariant Object Representation in the Ventral Visual Stream Is Not Dependent on Reward

Title

Neuronal Learning of Invariant Object Representation in the Ventral Visual Stream Is Not Dependent on Reward
Publication Type
Journal Article
Year of Publication
2012
Journal
Journal of Neuroscience
Volume
32
Issue
19
Pagination
6611 – 6620
Date Published
09/2012
ISSN
0270-6474
Abstract

Neurons at the top of primate ventral visual stream [inferior temporal cortex (IT)] have selectivity for objects that is highly tolerant to variation in the object's appearance on the retina. Previous nonhuman primate (Macaca mulatta) studies suggest that this neuronal tolerance is at least partly supported by the natural temporal contiguity of visual experience, because altering that temporal contiguity can robustly alter adult IT position and size tolerance. According to that work, it is the statistics of the subject's visual experience, not the subject's reward, that instruct the specific images that IT treats as equivalent. But is reward necessary for gating this type of learning in the ventral stream? Here we show that this is not the case—temporal tolerance learning proceeds at the same rate, regardless of reward magnitude and regardless of the temporal co-occurrence of reward, even in a behavioral task that does not require the subject to engage the object images. This suggests that the ventral visual stream uses autonomous, fully unsupervised mechanisms to constantly leverage all visual experience to help build its invariant object representation.

Short Title
Journal of Neuroscience