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Abstract:
Abstract: We compared the neural correlates of different
forms of episodic memory retrieval using PET. In particular, we
investigated three issues. First, in contrast with lesion data,
Cabeza et al. (1997) found similar prefrontal cortex (PFC)
activations for recall and recognition. This result could reflect
the use in this study of associative rather than simple recognition
(SRN). Second, PET studies have found medial temporal lobe (MTL)
activations for word-stem cued recall (WSCR) but not for
associative cued recall (ACR), suggesting a different role of MTL
in these two forms of recall. Finally, although PFC lesions impair
both recall and context memory (CM), it is not clear if these two
forms of strategic retrieval engage the same or different PFC
regions. In the present study, subjects studied words or
word-pairs, and were then scanned while performing SRN, WSCR, ACR,
or CM. Preliminary analyses yielded three main results: (1) left
ventrolateral PFC was more activated for ACR than for SRN; (2)
right MTL was more activated for WSCR than for ACR; and (3) left
dorsolateral PFC was more activated for ACR than for CM whereas
right dorsolateral PFC showed the converse pattern. In sum, the
neural correlates of episodic retrieval vary flexibly with changes
in retrieval task demands.
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