Positive Slow Wave of ABR and the Inferior Colliculus

Experimental Study by Using Electrical Stimulation of the Inferior Colliculus

Abstract

Our previous experimental study indicated that the ABR consisted of, at least, fast components and slow positive component. Furthermore, it was revealed that the inferior colliculus (IC) had a close relation to the slow component of the ABR, and acoustic stimuli evoked a large negative potential in the IC and electrically positive field surrounding the negative potential.
In order to reveal the electrical relation between the evoked potential of the IC and the slow positive wave of the ABR, electrical stimulation was applied to the lateroventral part of the IC where nerve fibers penetrate into the IC. Thus, the evoked potentials in the IC and the ABR were recorded.
The evoked potential of the IC was large negative wave and the ABR was slow positive wave, when the electrical stimuli were applied. These waves look like ones evoked by acoustic stimuli.
As result, the large negative potential of the IC plays important role to form the slow positive wave of the ABR, however, it might not be essential for generation of the several sequential fast waves of the ABR.