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Abstract:
Abstract: Extrastriate areas have been implicated in
processing visual word forms, although the particular functional
contributions of these regions are disputed. The present study
tests whether left extra-striate regions are sensitive to word
identity information that transcends the particular visual features
of a word. To test this, we repeatedly presented a standard word
(i.e. 'read') every 800 msec, and occasionally inserted one of two
probe events that contained non-habituated visual features: a word
identity probe (i.e. 'READ') or a word probe containing the same
letters (i.e. 'DARE'). Event-related fMRI analyses revealed
equivalent responses to all probe events in early visual and
bilateral parietal areas. However, responses in left extra-striate
regions near the occipital temporal boundary demonstrated reduced
activation to word identity probes relative to the other probes,
suggesting these regions are sensitive to feature invariant word
identity information. Similar effects were also demonstrated in
left superior temporal and left frontal regions, presumably related
to habituation of specific phonological and semantic information. A
second experiment extends this paradigm to dissociate visual word
form processes from phonological processes by using standard words
(i.e. 'rows') and probes that carry identical vs. different in
phonological information (i.e. 'ROSE' vs. 'SORE').
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