Rapid inhibition in the cochlear nuclear complex of the chinchilla

Robert E. Wickesberg

Research output: Contribution to journalArticlepeer-review

Abstract

This study examined responses to pairs of clicks recorded extracellularly from single units in ventral cochlear nuclei (VCN) of ketamine-anesthetized chinchillas. The response to the trailing click was suppressed for interclick intervals of 1 and 2 ms, but little suppression was observed for an interclick interval of 4 ms. To determine whether any suppression originated in the dorsal cochlear nucleus (DCN), responses to click pairs were recorded before and after injecting lidocaine in the deep layer of the DCN. For 19% of the neurons (7/37), the response to the trailing click increased following the injection, which is consistent with lidocaine reducing delayed inhibition from the DCN. Unexpectedly, for 62% of the units (23/37) the response to the initial click decreased after lidocaine administration. Three units (3/37 or 8%) showed a combination of both responses. For 52% of the units with a decreased response (12/23), the reduction occurred only for loud clicks (≤30 dB above threshold), while at intensities 20 dB lower, responses to pairs of clicks were unchanged. No changes in spontaneous rate were observed. Following lidocaine injections, the tuning curves of 7/12 neurons tested had increased thresholds, but only around the characteristic frequency. These results indicate the presence of two rapid inhibitory inputs onto VCN neurons.

Original languageEnglish (US)
Pages (from-to)1691-1702
Number of pages12
JournalJournal of the Acoustical Society of America
Volume100
Issue number3
DOIs
StatePublished - Sep 1996
Externally publishedYes

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Acoustics and Ultrasonics

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