Efferent gating of human auditory attentional processes

Brainstem evoked potentials were measured while subjects reduced either frontalis or lips/throat activity in response to visual information regarding EMG activity while attending to dichotically presented click stimuli. An inhibition of left ear activity occurred at the level of the cochlear nucleus (Wave 1) during articulatory muscle activity, suggesting that the right ear advantage is related to active inhibition of ipsilateral auditory pathways. Contralateral central inhibition of disattended information at the level of the brainstem (Wave 5) was also implicated. A neurophysiological model accounting for both attenuation of irrelevant stimuli and vigilance for high priority information is proposed.