Positive Slow Wave of ABR and the Inferior Colliculus

Observations of Potentials Inside and Outside of the Inferior Colliculus

Abstract

An animal experiement previously performed indicated that the ABR was considered to be consisted of at least two components; one is the fast component (wave I, II, III, IV, V, VI, VII) and the other is the positive slow component with the peak observed within the latency of the IV or V waves.
In order to investigate the origin of the slow component, in this study the evoked potentials were recorded at various points in the inferior colliculus, and the field map was consecutively made at the frontal and the sagittal sections. Acoustic stimuli evoked a large negative potential, and there observed the electrical positive field surrounding the negative potential and this positive field was recorded as a positive potential from the surface of the cortex. Therefore, the slow wave of the ABR is considered to have a close relation to the activity of the inferior colliculus evoked by acoustic stimuli. The origin of the fast waves, however, can not be estimated by this experiment.