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Abstract:
In a previous study (Jha & McCarthy, 2000), a face
working memory delayed-recognition task was used to examine
prefrontal (PFC) and fusiform (FFG) activity as memory load varied.
Within both PFC and FFG, increases in memory load resulted in
greater transient activity to memory cues. Within PFC, these
transient responses were followed by load insensitive sustained
delay activity. Activity within FFG returned to baseline during the
delay-interval. Here we examined the effect of distraction on
sustained delay activity. A 3-face memory cue was followed by an
18-sec delay-interval that ended with the presentation of a 1-face
memory probe. The subjects' task was to determine if the memory
probe matched any of the memory cue faces. During the delay
interval, a random number of previously unseen faces,
phase-scrambled faces (unrecognizable as faces), or no distracting
stimuli were presented. Transient responses to the memory cues were
comparable across all trial types within PFC and FFG. Within PFC,
delay activity was greatest during face-distraction followed by
lower amplitude activity for the scrambled-face and no distraction
trials. Within FFG, delay activity was greatest during
face-distraction followed by scrambled-face distraction. No delay
activity was observed during the no-distraction trials. Thus, delay
activity within PFC may reflect operations needed to prevent
task-specific distraction whereas FFG activity likely reflects
sensory processing of distractors.
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