Electrophysiologic Correlates of Attention versus Stimulus Competition in Young Male and Female Listeners

Abstract

The effects of attention and stimulus competition on the late auditory-evoked potential (LAEP) were compared in 10 young males and 10 young females. Listeners attended to discriminably different oddball tonal sequences presented binaurally or monaurally. Peak amplitudes in response to the frequent tones were measured for N1, P2, and early and late N2 (N2e and N21) components of the LAEP Whereas N1 amplitudes increased, the amplitudes of P2 decreased when listeners attended to, rather than ignored, the tones. Competition effects for both N1 and P2 resulted in reduced amplitudes in the presence of contralateral competition. Although findings with N2e and N21 suggested possible attention and competition effects, as well as gender differences, the data were inconsistent and will need further experimental verification. The present findings with the N1 and P2 components provide evidence that different neural processes underlie the attention and competition effects in the human brain.