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Abstract:
The reading span task is commonly used as a measure of
working memory capacity (Daneman and Carpenter, 1980). One version
of the task involves simultaneously evaluating a series of
sentences and remembering the final word of each sentence. Because
of its simultaneous processing and storage requirements, it can be
characterized as a dual task. We asked the following questions: 1)
which regions are implicated in performance of the reading span
task (RST) and its components: sentence comprehension (SC) and
verbal working memory (VWM)? 2) does sentence comprehension recruit
a set of areas implicated in verbal working memory? 3) could
performance decrements in the dual task be explained by
interference between the separate task components? 4) are there any
dual task-specific activations? Eight subjects were scanned while
they performed four pseudorandomly interleaved trial types: a) SC:
evaluation of 5 statements as true or false followed by a
left/right button press; b) VWM: passive reading of 5 narrative
sentences followed by recall of the final word of each sentence; c)
RS (dual task): evaluation of 5 T/F statements followed by recall
of final words; and d) control: a visuomotor control. Activations
during the dual task were found in L inferior frontal gyrus, L
precentral gyrus, R middle frontal gyrus, R occipital
cortex/cerebellum and bilateral posterior parietal and cingulate
cortices. SC recruited a number of the same areas as VWM. The
overlap between SC-related and VWM-related activations could
explain dual task performance decrements. There were no activations
specific to the dual task.
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