Effects of spatial attention on the brain stem frequency-following potential.

Can spatial attention or orienting affect human auditory information processing as peripheral as on the brain stem level? More specifically, is the reduction of the latency of the frequency-following potential (FFP; an evoked lower brain stem response) that we described in an earlier Neuroreport article really specifically attention-related? Here we demonstrate that, indeed, exogenous intramodal (auditory) spatial orienting, but not a transient modulation of general arousal, reduced the latency of the FFP by 27 micros; there were no effects on the FFP-amplitude. Although it might seem small, this reduction may be relevant in spatial hearing. We conclude that under certain conditions spatial attention can affect auditory information processing already on the brain stem level.