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Abstract:
Event-related potentials (ERPs) were obtained under two
conditions to study the effects of distracting stimuli on
attention. For the sustained attention condition, subjects
performed an auditory continuous performance task (CPT) that
incorporated target detection (Go) and response inhibition (No-Go).
For the focused condition, the same CPT was performed with
distracting stories played concurrently. The P300 response to
target detection has a posterior maximum scalp distribution, while
the P300 to No-Go has a more frontal-central scalp distribution and
has been associated with frontal lobe functioning. ERPs were
averaged to Go and No-Go stimuli for both CPT conditions. Findings
revealed that P300 amplitude and scalp distribution did not differ
between the sustained and focused conditions for Go or No-Go. P300
latency differences were present between the conditions for both Go
and No-Go. The focused attention condition produced longer latency
than the sustained condition at all midline sites for Go stimuli,
and longer latency only at the frontal site for No-Go. P300
amplitude results indicate that the neural resources allocated to
the CPT task were not affected by distraction. The P300 latency
results suggest that screening of distracting information prolonged
the decision-making time to respond (Go) or inhibit responding
(No-Go). The No-Go P300 may represent the degree of frontal lobe
involvement in the task.
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