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Abstract:
Abstract: We examined brain mechanisms associated with the
deployment of voluntary visuospatial attention in a spatial cueing
paradigm. A visual arrow cue was followed by a 1000 ms delay period
after which subjects were required to make a stimulus
discrimination if a visual stimulus was presented at the location
cued by the arrow (50% probability). In different blocks, the
stimuli to which subjects attended were in either the upper or
lower visual hemifields and were either oriented Ts or moving dots.
Alpha-band (8-14 Hz) oscillatory was characterized in the period
between the presentation of the cue and stimulus onset. We found
that, starting approximately 500 ms after the onset of the cue and
lasting until the onset of the to-be-attended stimulus a focal
region of increased alpha-band activity was present over cortical
regions corresponding to the location of the to-be-ignored stimulus
location. We suggest this activity reflects active inhibitory
gating of stimulus locations that are likely to contain distractor
information. We hypothesize that oscillatory activity in this
frequency band may be a functional mechanism for active attentional
suppression.
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