Abstract
Adaptive behavior not only needs to select relevant information from the attention but also relies on deducing plausible interpretations of the information from the expectation. The former is known to operate in a center-surround inhibition manner, whether this manner is also at play within the latter, however, remains unclear. Here, subjects were asked to perform either an orientation or a spatial frequency discrimination task on the two consecutive gratings in Experiments 1 (where orientation was task-relevant) and 2 (where orientation was task-irrelevant), respectively. In both experiments, we manipulated the distance in orientation space between the expected and test gratings, ranging from Δ0° through Δ40° with a step size of 10°, to measure the profile of expectation. The prior expectation about the orientation of the subsequent grating stimuli was implicitly induced by the auditory cue, with 75% probability for the predicated orientation (Δ0°) and 6.25% possibility for each of non-predicted orientations (Δ10°, Δ20°, Δ30°, and Δ40°). Both experiments demonstrated a classical center-surround inhibition in expectation when subjects internally expected rather than visually attended an orientated stimulus, with the enhanced discriminability of expected orientation and decreased discriminability of orientations similar to the expected orientation relative to orientations more distinct from it. Altogether, our findings indicate for the first time that neural enhancement and suppression coexist in visual expectation that optimizes plausible interpretations during visual perception by attenuating interference from irrelevant and confusable representations.