Abstract
The question of whether attention makes sensory impressions appear more intense has been a matter of debate for over a century. Recent psychophysical studies have reported that attention increases the apparent contrast of visual stimuli, but there is still a controversy as to whether this effect is due to the biasing of decisions as opposed to the altering of perceptual representations and changes in subjective appearance. We obtained converging neurophysiological evidence while observers judged the relative contrast of Gabor patch targets presented simultaneously to the left and right visual fields following a lateralized cue (auditory or visual). This non-predictive cueing boosted the apparent contrast of the Gabor target on the cued side in association with an enlarged neural response in the contralateral visual cortex that began within 100 ms after target onset. The magnitude of the enhanced neural response in ventral extrastriate visual cortex was positively correlated with perceptual reports of the cued-side target being higher in contrast. These results suggest that attention increases the perceived contrast of visual stimuli by boosting early sensory processing in the visual cortex.
Meeting abstract presented at VSS 2012