Scalp distribution of the auditory evoked brainstem potentials in the guinea pig during monaural and binaural stimulation.
Auditory evoked brainstem potentials in response to monaural and binaural sound stimuli were observed by monopolar recording at five positions on the skull of the guinea pig. With monaural presentation the amplitudes of the first two potentials in the complex had a maximum at ipsilateral positions, the third potential was of uniform size at all recording positions, and the fourth and fifth potentials were largest at contralateral positions. The differing maxima of the negative and positive components of the individual potentials proved to be consistent with the theory of volume conduction. When sounds were presented binaurally the amplitudes of all potentials were symmetrical with respect to the vertex. Moreover, binaural interactions at the neural level could be inferred from the brainstem responses. The results indicate that the individual potentials in the complex are associated with activation of specific structures in the auditory pathway. This finding and the observed differences between the two sound modes have implications for clinical practice.
D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D001933:Brain Stem / Q000502:physiology*; D005072:Evoked Potentials, Auditory; D006168:Guinea Pigs; D011930:Reaction Time; D012535:Scalp