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Abstract:
Unlike the amygdala, orbital, insular, and anterior cingulate
cortices, retrosplenial cortex is generally believed to have no
role in emotion. A clear demonstration that the retrosplenial
cortex participates in emotional processing would challenge current
views of the cortical regions involved in emotion. Surprisingly,
many functional imaging studies involving emotionally salient
stimuli have observed significant activation in the retrosplenial
cortex, but little significance has been attributed to this. Our
recent fMRI study of threat-related spoken words showed that
retrosplenial cortex is more strongly and consistently activated
than any other region, and may contribute to the effects of emotion
on memory. The current study tests the hypothesis that
retrosplenial cortex activates during processing of emotionally
salient stimuli in general, that is, without respect to valence
(unpleasant/pleasant), modality (auditory/visual), or format
(verbal/pictorial). Four subjects were scanned during alternating
16" blocks of emotionally salient and matched neutral spoken words.
Emotionally salient words were either intensely unpleasant or
pleasant. Activation of retrosplenial cortex was observed with both
word types in 3 of 4 subjects. Location of activation with
unpleasant and pleasant words was identical within subjects.
Activation was stronger for pleasant words. One subject scanned
during visually presented pleasant words also activated
retrosplenial cortex in the same location. Data from additional
subjects scanned while evaluating visually presented words and
pictures will also be presented. These studies will provide a first
test of the hypothesis that retro-splenial cortex has a broad role
in the processing of emotionally salient stimuli.
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