Click spatial position influences middle latency auditory evoked potentials (MAEPs) in humans.

Middle latency auditory evoked potentials (MAEPs) were elicited by monaural and binaural clicks. The Na component (latency 15.8 msec) was larger in amplitude and shorter in latency at electrodes contralateral to the stimulated ear in monaural conditions, but showed no evidence of binaural occlusion. The Pa (28.4 msec) and Nb (42.0 msec) components did not change in amplitude or distribution as a function of the ear of stimulus delivery, but were smaller following binaural stimulation than would have been predicted from separately recorded monaural responses. These results indicate that functionally distinct generator systems are responsible for different components of the MAEP. The generators of the Na are more effectively activated by contralateral inputs. In contrast, the generators of the Pa and Nb receive equally effective and convergent inputs from the two ears.