| |
Abstract:
Abstract: The neural substrate underlying the production of
ASL was evaluated using PET in 16 right handed, congenitally deaf
(10 females and six males, 20 to 29 years) native ASL signers. The
subjects were scanned during three conditions: passively viewing,
repeating and generating a verb in response to, ASL nouns. This
paradigm has been used in previous studies of spoken word
production and was selected for purposes of comparison. Results
were in general congruent with these studies: repeating nouns was
associated with bilateral activity of motor areas; verb generation
with activation of the left operculum, left dorsolateral prefrontal
cortex (PFC) and right cerebellar hemisphere. Each contrast was
associated with activation of a different portion of the left
inferior parietal lobule: noun repetition with activation of SMG,
verb generation with activation of angular gyrus, and each contrast
was associated with activation of a different
corticostriatal-thalamocortical circuit: repetition with activation
of the motor loop (posterior putamen, ventralateral thalamus and
SMA); verb generation with activation of the prefrontal loop
(caudate, dorsomedial thalamus and PFC). In addition, both
contrasts were associated with activation of the left posterior
superior temporal gyrus: repetition with activation of BA 42/ 22;
generation with posterior BA22 and the contiguous superior temporal
sulcus, providing evidence for cross-modal plasticity in the
deaf.
|
