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Abstract:
Abstract: Distinguishing between task-relevant targets and
irrelevant stimuli is critical in generating goal-directed
behavior. Two ERP components associated with target detection are
the posterior Selection Negativity (SN) and the Frontal Selection
Positivity (FSP). We propose that the FSP indexes activity in
modality independent prefrontal selective attention networks and
that the SN indexes activity in modality dependent posterior
stimulus representation networks. We test this hypothesis in
auditory, visuo-spatial, and visuo-object target detection tasks.
The FSP peak latency was different in each task: 188 ms in
auditory, 236 ms in visuo-spatial, and 296 ms in visuo-object
target detection. When the FSP in each task from the same frontal
lead was overplotted, the waveform morphology was nearly identical.
This suggests that the FSP indexes the same process, occurring at
different latencies, in each type of target detection. The SN/FSP
was mapped at the peak of the FSP in each task. In auditory
detection the SN was located over superior temporal sites; in
visual object detection the SN was located over inferior temporal
sites; in visual spatial detection the SN extended dorsally to
superior parietal sites. Thus at the peak of the FSP the SN was
focussed over posterior sites overlying the cortical areas housing
the task-relevant stimulus representation. This is consistent with
interaction between networks of perceptual representation in
posterior cortex and selective attention networks in prefrontal
cortex.
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