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Abstract:
Although most functional neuroimaging studies have focused on
one cognitive function, it is clear that different cognitive
functions engage many of the same brain regions. These common
activations could reflect cognitive operations shared by these
functions (Cabeza & Nyberg, 2000). To investigate this issue,
we compared the neural correlates of episodic memory retrieval and
working memory within-subjects using fMRI. In the episodic
retrieval task, subjects made Remember/Know/New decisions to single
words. In the working memory task, subjects maintained 2 columns of
2 words each for 12 sec, and then decided whether a probe word had
occurred in the left column, the right column, or was new.
Preliminary random effects analyses with 9 subjects were performed
on data from the retrieval phase of both tasks. Compared to a
sensorimotor baseline, both tasks engaged a common network of
regions, including left prefrontal, left parietal, left temporal,
right cerebellar, and medial occipital regions. Right prefrontal,
cerebellar, and precuneus regions were more activated for episodic
than for working memory, whereas bilateral posterior prefrontal and
left parietal regions were more activated for working than for
episodic memory. The common network for episodic memory retrieval
and working memory retrieval may reflect retrieval operations that
apply to both long-term and short-term memory stores.
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