The effects of generalized seizure activity on the cerebellar auditory potential.

The effects of generalized seizure activity (GSA) on the primary cortical component of the cerebellar auditory evoked potential [CERAEP] were studied in the awake rat. GSA was induced by electroconvulsive shock (ECS) [80 mA for 600 ms]. CERAEPs proved largely resistant to GSA, even during the ictal period. Any minor alterations to the waveform were very transient and normal morphology was restored within 1-2 min after ECS. Overall, there was a mean decrease in amplitude of 2.6 microV associated with an increase in latency of 0.2 ms. These findings are consistent with those of GSA on the fast and slow components of the brainstem auditory evoked potential and imply that activity generated in the more caudal parts of the central auditory system is largely invulnerable to GSA. In contrast, a later component of the CERAEP waveform of uncertain origin was totally abolished by the action of ECS.