El. Jocoy et al., CONCURRENT VISUAL TASK EFFECTS ON EVOKED AND EMITTED AUDITORY P300 INADOLESCENTS, International journal of psychophysiology, 30(3), 1998, pp. 319-328
Using an oddball stimulus presentation paradigm, the effects of divide
d attention on auditory P300s were studied. Auditory attention was eit
her divided or focused, depending on the demands placed on subjects du
ring the performance of a concomitantly presented visual task. Two typ
es of auditory tasks were performed under each of the two auditory att
ention conditions. In one, subjects responded to infrequently presente
d high pitched tones (oddball stimuli). In the other they responded to
the occasional omission of a stimulus in an otherwise rhythmically pr
esented chain of stimuli. P300s and reaction times were recorded to bo
th the rare tones and the omissions. The Sternberg visual memory task
was used to manipulate the subject's auditory attention state. Subject
s actively performed the Sternberg task during the divided auditory at
tention condition, whereas during the focused attention condition they
were not required to respond to the visual stimuli. During focused au
ditory attention, evoked auditory P300s were both larger and faster th
an their emitted counterparts. During divided attention, auditory P300
s were reduced in amplitude but latency was unaffected. Evoked auditor
y P300s showed evidence of containing P300a as well as P300b component
s, particularly when attention was shared with the visual task. (C) 19
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