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Abstract:
H20-15 PET images were obtained while 14 native deaf signers
and 10 hearing ASL-naive subjects watched a videotaped performance
of transitive actions (HTA) (e.g. towel folding) and two-handed ASL
nouns. Results were quantified via Statistical Parametric Mapping
(SPM 96). Deaf subjects viewing ASL relative to HTA showed
extensive left inferior frontal and bilateral medial prefrontal
activation (BA 10, 44, 46, 47). Temporal activation included left
anterior auditory association cortex, insula, and fusiform, and
bilateral lateral temporal-occipital cortex (BA19). Parietal
activation included bilateral superior parietal lobule (BA7) and
cuneus, and right angular gyrus. Hearing subjects activation was
limited to left auditory cortex (BA42). HTA-viewing hearing
subjects showed right-lateralized frontal (medial prefrontal, and
inferior rolandic, BA 1-4, 6, 8) and left-lateralized insula
activation. Bilateral activation occurred in the superior parietal
lobule (BA7) and cuneus. Extensive bilateral activation occurred in
fusiform, lingual gyrus (BA18), and lateral occipital regions
(BA37). Deaf subjects viewing HTA relative to ASL displayed neither
frontal nor temporal activation. Parietal activation included
bilateral cuneus and right angular gyrus. Occipital activation
included bilateral lingual and fusiform gyri, lateral occipital,
and striate regions. These differential activation patterns
highlight a specialized linguistic processing system for sign
language. Commonalities in ventral, temporal, and parietal
activation across HTA conditions implicate object and praxic
recognition during movement perception.
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