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Abstract:
Abstract: Perceptual categorization has been widely explored
using formal theories of categorization; however, relatively little
is known about how the processes involved in categorization might
be carried out by the human brain. In these studies, we used
functional imaging (fMRI) to map out areas of the brain that might
be involved in perceptual categorization of novel stimuli. In an
extension of an experiment by Reber, Stark, and Squire (1998),
participants learned a category of irregular polygons and then
categorized members and nonmembers of the learned category; we
observed differential hippocampal and parahippocampal activation
during presentation of nonmembers versus members of a category. In
another experiment, we observed differential fusiform gyrus and
medial occipital gyrus activation during presentation of high-level
versus low-level distortions of a category. Differences between
these results and those of Reber et al. will be discussed in terms
of stimulus differences and task requirements. Together, they
suggest that a variety of cortical areas may participate in
different aspects of perceptual categorization.
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