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Abstract:
Corbetta, Miezin, Dobmeyer, Shulman, and Petersen's classic
1991 positron emission tomograpy (PET) study of divided and
selective attention found increases in different extrastriate
regions depending on whether the subjects selectively attended to
color, shape, or speed information. This finding suggested that
attention to a neural channel of information is mediated by
increasing the activity in this channel. However, these effects
could have been due to preparation or memory processes rather than
modulation of input. This study was therefore replicated with
high-density (128-channel) event-related potentials (ERP). As in
the original experiment, subjects were presented with an array of
moving colored rectangles twice in a row (200 msec inter-stimulus
interval, ISI). Subjects looked for changes between the two
presentations in either color, shape, or speed (selective
attention) or in all three (divided attention). An additional
question of interest is whether the results generalize for longer
ISIs. 200 msec is well within the period of iconic memory. A longer
ISI would require greater reliance on working memory. Comparisons
are made to an fMRI replication experiment previously collected
(Dien, Buonocore, Hopfinger, & Mangun, in preparation).
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