Montaser-Kouhsari L, Rajimehr R, 2004, "Attentional modulation of brief orientation adaptation to unresolvable patterns" Perception 33 ECVP Abstract Supplement
Attentional modulation of brief orientation adaptation to unresolvable patterns
L Montaser-Kouhsari, R Rajimehr
Selective visual attention modulates neuronal activation in various cortical areas. This type of neuronal modulation happens even in the early stages of visual processing where specific attributes of visual stimuli are processed. We investigated the effect of visual attention on brief orientation adaptation while subjects were unaware of the orientation of the adapting stimulus. Brief adaptation to an oriented grating impairs identification of nearby orientations by broadening orientation selectivity and changing the preferred orientation of individual V1 neurons. In the first experiment, subjects performed a delayed match-to-sample task in the peripheral visual field. They were asked to report whether two briefly flashed Gabors differ in orientation or not. The second Gabor patch (test stimulus) was preceded by a 400 ms adapting stimulus (unresolvable Gabor patch). In the second experiment, subjects performed the same task concurrent with a secondary task (even/odd judgment) at the fixation point during the adaptation period. Results demonstrated the brief adaptation to unresolvable orientation in the first experiment but no adaptation in the second experiment. We suggest that the unresolvable orientation information selectively activates the primary visual cortex and this activation (as revealed by brief orientation-adaptation paradigm) is modulated by attention.
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