A possible thalamic component of the auditory evoked potential in the rat

An attempt is described to identify a thalamic component of the auditory evoked potential in the rat. Auditory potentials were recorded simultaneously from skull locations over the thalamus and the primary auditory cortex. From over the thalamus a slow positive response was recorded with a mean peak latency of 7.3 ms. This preceded the primary cortical response by 1.2 ms. It is concluded that this potential is a more likely candidate for a thalamic response than either a late high frequency component of the brainstem auditory evoked potential or else one of the early components of the middle latency auditory evoked potential.