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Abstract:
Although the degree of semantic analysis performed on a
verbal stimulus is correlated with the subsequent memorability of
that stimulus, nonsemantic features of verbal stimuli are often
retained and can influence the nature and durability of a memory.
While neuroimaging experiments of verbal memory encoding have
identified regions differentially active for rememebered words,
most have done so in the context of semantic orieinting tasks.
Therefore, an open question is how other types of processing affect
brain regions associated with verbal memory encoding. Eighteen
participants were imaged using functional MRI to explore whether
regions predicting successful verbal memory encoding during
semantic (abstract/concrete) decisions would continue to predict
encoding during structural (uppercase/lowercase) decisions.
Consistent with prior studies, left inferior frontal and fusiform
regions were more active during semantic than structural decisions,
and activity was greater for remembered than forgotten words during
semantic decisions. Critically, structural decisions yielded
significantly greater activity for remembered than forgotten words
in these regions, providing evidence that a common frontal-temporal
network supports verbal memory encoding irrespective of orienting
task. Further analysis revealed activity associated with successful
encoding in the right precentral sulcus, suggesting other regions
may also play a role in verbal encoding during nonsemantic
processing. Supported by NIH (MH57506, NS32979) and McDonnell
Foundation (99-63/9900003).
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