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Abstract:
Abstract: While brain imaging studies have focused on
representation of spatial and symbolic information in working
memory, less research has addressed where online representations of
incentive value might be stored. Using event-related fMRI (1.5T GE
scanner, 16 sagittal slices / whole brain, TR=2 sec), we examined
brain areas activated by anticipation of monetary reward during an
incentive delay task (Schultz et al., 1998). Participants saw
colored cues signalling that they could either potentially make
money ("reward": $1.00) or not ("control"), waited a variable delay
(~2250 msec), and then responded to briefly presented targets (~210
msec) with a button press. Reaction time to reward targets was
significantly faster than to control targets. Comparison of BOLD
contrast during reward delay periods versus control delay periods
revealed differential recruitment of mesial prefrontal cortex (BA
32), nucleus accumbens, and cerebellar vermis in a majority of
participants, and spatially normalized group maps confirmed these
observed patterns. These findings indicate that medial prefrontal
circuitry may play a role in working memory for incentive
information.
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