Evoked cisterna cerebellomedullaris potentials in the clinically normal dog.

Cisterna cerebellomedullaris potentials (ECMP), evoked by percutaneous electrical stimulation of the ulnar and sciatic nerves, were recorded and averaged in each of 38 anesthetized, clinically normal dogs. The amplitude, latency, duration, and form of the recordings were characterized and compared with results obtained when the recording needle was positioned laterally, rostrad, caudad, and superficially to the cisterna cerebellomedullaris and in the brainstem. Recordings were compared with averaged evoked cerebrocortical potentials (ECP). The ECMP and ECP recordings were compared in dogs maintained at light planes of anesthesia, following cardiac arrest, and following severance of the spinal cord at L1 (in 14 dogs). The ECMP recordings were found to have greater amplitude and to be more consistent, complex waveforms than the ECP. The method of recording the ECMP was found to be straightforward. Thus this method of ECMP recording appeared suitable for clinical application.