Long-range, pattern-dependent contextual effects in early human visual cortex.

ABSTRACT: The standard view of neurons in early visual cortex is that they behave like localized feature detectors. Here we demonstrate that processing in early visual areas goes beyond feature detection by showing that neural responses are greater when a feature deviates from its context compared to when it does not deviate from its context. Using psychophysics, fMRI, and electroencephalography methodologies, we measured neural responses to an oriented Gabor ("target") embedded in various visual patterns as defined by the relative orientation of flanking stimuli. We first show using psychophysical contrast adaptation and fMRI that a target that differs from its context results in more neural activity compared to a target that is contained within an alternating sequence, suggesting that neurons in e

SUBMITTER: Joo SJ 

PROVIDER: S-EPMC3350565 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature