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Abstract:
We investigated the neural correlates of the Stroop
interference effect using event-related brain potentials.
Individuals pressed a key to identify the color of a stimulus or
the identity of the word presented based upon a preset cue, with
color and word identification trials randomly intermixed within a
block of trials. Attentional set was manipulated by varying the
proportion of word identification trials from 25% to 50% between
blocks of trials. In the 25% word reading condition P3 amplitude
was greater for congruent than incongruent stimuli over left
posterior regions. In contrast, for the 50% word reading condition
P3 amplitude was greater for incongruent than congruent stimuli and
this effect was accompanied by a sustained negative displacement
over anterior regions. These findings indicate that attentional set
modulates the activity of neural systems supporting performance of
the Stroop task with frontal systems being most active when the
processing system is biased toward word reading and color naming is
required.
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