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Abstract:
Neuroimaging studies have implicated different areas of
prefrontal cortex in episodic retrieval tasks, and there is
considerable interest in the role of specific prefrontal regions in
specific aspects of episodic retrieval. In this experiment, changes
in regional cerebral blood flow (rCBF) were examined under
relational and non-relational retrieval conditions. Prior to
scanning, subjects studied a list of word pairs and were asked to
try to remember them. During scanning, participants performed a
recognition test in which they made relational or non-relational
judgments. Relational judgments required participants to indicate
whether two words had appeared together on the study list. Some
words were paired with the same word they had been paired with at
study (relational retrieval with pair reinstatement), whereas
others were paired with a different word (relational retrieval
without pair reinstatement). In the non-relational retrieval
condition, participants were instructed to indicate whether either
of the words in a test-pair was studied previously, regardless of
the study pairing. The positron emission tomography data indicated
that both types of relational retrieval are associated with
increased rCBF in the left ventral prefrontal cortex, while
non-relational retrieval is associated with increased rCBF in the
right dorsal prefrontal cortex. Results thus suggest that specific
prefrontal regions may be associated with specific aspects of
episodic retrieval.
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