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Abstract:
Abstract: Affiliation: Many patients have been reported with
selective deficits for nouns and verbs (e.g. Daniele, et al, 1994),
leading to the claim that they have different neural
representations, with verbs being processed by the left pre-motor
cortex and nouns by left fronto-temporal regions (Damasio &
Tranel 1993). This picture conflicts with results from recent PET
studies with healthy subjects which fail to find anatomical
differences between nouns and verbs (Warburton et.al. 1996).
However, these studies have, for the most part, used
under-constrained tasks and stimuli which were not controlled for
important variables such as word frequency and imageability. In an
effort to remedy this situation, we carried out a PET study to
explore the neural representation of nouns and verbs, controlling
for word familiarity, frequency, word length and imageability. We
found no regional specialisation as a function of form-class.
However, both nouns and verbs significantly activated left Broca's
area, extending into BA47, as well as the left fusiform gyrius with
some (albeit reduced) additional activation in the right homologous
region. This pattern is consistent with our recent theoretical
claims that conceptual knowledge is represented within a single
unitary semantic system (Durrant-Peatfield, Tyler, Moss & Levy,
1997). Daniele et al. (1994). Neuropsychologia, 32, 1325-1341.
Damasio & Tranel (1993). Proc. Natl. Acad. Sci. USA, 90,
4957-496. Warburton et.al. (1996). Brain, 119, 159-179
Durrant-Peatfield et al. Proc Nineteenth Annual Conference of the
Cognitive Science Society, Erlbaum, 193-198.
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