DISCHARGE SUPPRESSION IN THE SILENT INTERVAL PRECEDING THE TONE BURSTIN PAUSE-BUILD UNITS OF THE DORSAL COCHLEAR NUCLEUS OF THE UNANESTHETIZED DECEREBRATE CAT

A recent intracellular study of dorsal cochlear nucleus (DCN) neurons in vitro by Manis [P. B. Manis, J. Neurosci. 10, 2338-2351 (1990)] sug gests that the expression of the pause-build discharge pattern is in l arge part dependent on hyperpolarization of their membrane potentials in a period just preceding a depolarizing stimulus (''hyperpolarizatio n conditioning'' hypothesis). Our examination of the activity of a sam ple of pause-build units (n = 72) revealed suppression of discharge ac tivity during a time window of the silent interstimulus interval (SII) just preceding the tone burst relative to the spontaneous rate in 74% of all units. The discharge suppression of a subset of DCN pause-buil d units in the SII satisfies a requirement of the ''hyperpolarization conditioning'' hypothesis, and thus supports the hypothesis.