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Abstract:
An important issue in cognitive neuroscience concerns the
neural representation of conceptual knowledge. Some
neuropsychological and neuroimaging studies argue for neural
specificity as a function of specific types/categories (Caramazza
& Shelton, 1998; Martin et al, 1996) while others argue for an
undifferentiated neural system (Tyler et al, 2000). In previous
studies, using PET and fMRI, we found no evidence for neural
specialization for the processing of written words denoting living
and non-living things (Devlin et al, submitted). In the present
study, we extend this research by asking whether there is neural
specialization for pictures of living and non-living things when
several "nuisance" variables are carefully controlled. To be
consistent with our previous studies, we used a semantic
categorization task. Subjects saw 3 cue pictures presented
sequentially on a computer screen and made a semantic decision as
to whether a fourth target picture belonged to the same category.
Pictures came from the categories of Animals, Fruits/Vegetables,
Tools and Vehicles. We found no significant differences in
activation as a function of either category or domain. These
results are consistent with our previous findings and suggest that
there is no neural specialization for the processing of concepts in
different categories and domains. (PT is supported by Foundation
for Science and Technology, Lisbon, Portugal).
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