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Abstract:
Abstract: We employed functional magnetic resonance imaging
(fMRI) to investigate neural mechanisms implicated in encoding and
recognition of affectively negative stimuli. We hypothesized that
the processing of emotionally charged material would elicit more
activation in the right hemisphere limbic structures than the
processing of neutral material. Eight right-handed males were
scanned during the performance of an emotional memory task. The
task consisted of encoding, rehearsal, and recognition of either
neutral or negative series of words. Analysis of behavioral data
supported previous findings of facilitated retrieval of emotional
material. Analysis of neuroimaging data using Statistical
Parametric Mapping (SPM 96) revealed several interesting results.
First, encoding of the negative words resulted in significantly
stronger activation in the bilateral inferior frontal gyrus (BA45),
medial frontal gyrus (BA 9) and inferior parietal gyrus (BA 39),
than encoding of the neutral words. Second, recognition of the
negative words produced greater activation in the left hippocampus,
left cingulate, and left medial frontal gyrus, than recognition of
the neutral words. Furthermore, a conjunction analysis of both
contrasts revealed significant activation in the left medial
frontal gyrus, left inferior frontal gyrus, and left hippocampus.
Thus, in contrast to our hypothesis, encoding and retrieval of
negative stimuli, as compared with neutral stimuli, elicited more
activation in the left cerebral areas associated with the verbal
memory function.
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