title: Late components of auditory event-related potentials to eight equiprobable stimuli in a target detection task.
abstract: Fourteen normal subjects undertook a target detection task in which eight different but equiprobable stimuli were presented in an unpredictable sequence (four tone frequencies to either the left or the right ear). One tone/ear combination was designated as a target, to be responded to with a rapid button press. Event-related potentials were recorded from an array of six scalp electrodes. In Condition 1 no responses were required; in Condition 2 a response was required to the highest tone in one designated ear; in Condition 3 a response was required to the second highest tone in the ear opposite to the Condition 2 target. Event-related potentials to the no-task condition (1) included a P3-type late positive component. P3 increased in amplitude to target tones in Conditions 2 and 3, but showed equally large amplitude increases and some decrease in latency to nontarget tones in those conditions. However, a frontal Slow Wave component was elicited more specifically by target stimuli. An attended ear effect was evident in a processing negativity that extended for some hundreds of milliseconds prefrontally, but tended to be comprised of two separate negativities over fronto-central locations.
authors.forename: W C
authors.initials: WC
authors.lastname: McCallum
authors.forename: K
authors.initials: K
authors.lastname: Barrett
authors.forename: P V
authors.initials: PV
authors.lastname: Pocock
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology; D001288:Attention / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology; D004292:Dominance, Cerebral / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010897:Pitch Discrimination / Q000502:physiology*; D011337:Probability Learning; D012815:Signal Processing, Computer-Assisted