MICROELECTRODE STUDY OF VENTRAL COCHLEAR NUCLEUS OF THE CAT

Abstract

Electrical activity recorded with tungsten microelectrodes advanced through cerebellum and brain stem to cochlear nucleus of unanesthetized cat shows "slow wave" and single unit responses to various sounds. A click stimulus produces characteristic slow wave responses at the tip of an electrode lying near to or within the cochlear nucleus, and the actual anatomical locus of the tip can be reliably predicted from close examination of the latency and wave shape of these responses. Response areas for single units like those previously described in anesthetized preparations occur in both dorsal and ventral cochlear nuclei. Furthermore, in both nuclei, tones suppress spontaneously active units, and units driven by one tone can be suppressed by a second tone sounded simultaneously. If significant differences exist in cochlear nucleus activity recordable from anesthetized and unanesthetized preparations, these have thus far eluded the analysis.