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Abstract:
Complex syntactic structures activate areas which are also
activated by verbal working memory tasks. These WM tasks appear to
use a motor network, e.g. Baddeley's articulatory rehearsal. It has
been proposed that articulatory rehearsal may play a particularly
prominent role in recovery after readers initially construct the
wrong syntactic structure for a syntactically ambiguous sentence
(Caplan and Waters, 1990). We presented 16 normal volunteers with
unambiguous control sentences and sentences which remain
syntactically ambiguous for at least three words and then must be
assigned the less preferred structure. PET scans were made while
subjects read sentences in each condition (two scans per
condition). The syntactically ambiguous sentences showed increased
blood flow in left precentral cortex (Talairach and Tournoux
coordinates -48,20,28), and right caudate (18,6,16) and cerebellum
(38,-80,-24). These areas may form a motor pathway which supports
articulatory rehearsal. An additional activation was seen in the
left superior frontal gyrus (-14,36,44). This activation is likely
to reflect aspects of semantic evaluation of the alternative
meanings, as it has previously been shown to be activated in
anomaly detection tasks (Broere et al, 1997). Broere et al. (1997).
Journal of Cerebral Blood Flow and Metabolism 17 (Supplement 1):
S265. Caplan, D., & Waters, G.S. (1990). In Vallar and
Shallice, (Eds.), Neuropsychological impairments of short-term
memory, Cambridge: Cambridge University Press.
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