Predictive coding in the visual cortex: a functional interpretation of some extra-classical receptive-field effects

Author: R P Rao1, D H Ballard
1 Salk Institute, Sloan Center for Theoretical Neurobiology, La Jolla, California, USA.
Conference/Journal: Nat Neurosci
Date published: 1999 Jan 1
Other: Volume ID: 2 , Issue ID: 1 , Pages: 79-87 , Special Notes: doi: 10.1038/4580. , Word Count: 119

We describe a model of visual processing in which feedback connections from a higher- to a lower-order visual cortical area carry predictions of lower-level neural activities, whereas the feedforward connections carry the residual errors between the predictions and the actual lower-level activities. When exposed to natural images, a hierarchical network of model neurons implementing such a model developed simple-cell-like receptive fields. A subset of neurons responsible for carrying the residual errors showed endstopping and other extra-classical receptive-field effects. These results suggest that rather than being exclusively feedforward phenomena, nonclassical surround effects in the visual cortex may also result from cortico-cortical feedback as a consequence of the visual system using an efficient hierarchical strategy for encoding natural images.

PMID: 10195184 DOI: 10.1038/4580