[N2 effect on non-target event-related brain potentials during auditory selective response task].

Objective. To study N2 effect and its feature on non-target event-related brain potentials during auditory selective attention. Method. The subjects were 16 healthy right-handed male volunteers aged 23.2 +/- 2.1 years. The stimuli were male voice of one-digit numbers (2 to 7), which were single syllable pronunciated in Chinese, and appeared randomly with equal probability. The subjects were asked to press a switch as soon as the target signal (odd or even number) was heard but make no response to the non-target signal. EEG signals at 9 locations were recorded. Result. 1) A negative component N280 (N2 effect) was found after non-target stimuli as compared to target stimuli, which was significant in the frontal brain locations; 2) P3 was smaller and its peak appeared later in non-target ERPs than in target ERPs. Conclusion. N2 effect was also elicited by non-target stimuli during auditory modality. We assume that N2 effect might reflect the readjusting of model stored in working memory at the frontal brain.