Crossed cochlear influences on monaural temporary threshold shifts

R. Rajan, B. M. Johnstone

Research output: Contribution to journalArticleResearchpeer-review

62 Citations (Scopus)

Abstract

Temporary threshold shifts (TTS) of the cochlear action potential in one (ipsilateral) ear, caused by a brief intense pure tone, were reduced either by 1. (1) contralateral acoustic stimulation at the same frequency, or 2. (2) destruction of the contralateral cochlea. The effect of contralateral cochlear destruction persisted, though slightly reduced in effect, after a delay of one hour between the destruction and the ipsilateral exposure. Contralateral acoustic stimulation had no effect after a delay of 10 min. The effect of contralateral cochlear destruction could be blocked by strychnine, a known antagonist of auditory efferent activity. However, contralateral cochlear destruction resulted in none of the effects upon normal ipsilateral thresholds or input-output curves for the action potential classically seen when the efferent pathways are stimulated. The results suggest that the crossed effects reported here are due to a complex interaction between the activity in both cochleas, possibly resulting in a reduction in a central inhibitory influence on an efferent feedback pathway that is then expressed during the ipsilateral exposure.

Original languageEnglish
Pages (from-to)279-294
Number of pages16
JournalHearing Research
Volume9
Issue number3
DOIs
Publication statusPublished - 1 Jan 1983
Externally publishedYes

Keywords

  • contralateral acoustic stimulation
  • contralateral cochlear destruction
  • effects on N
  • guinea pigs
  • reduced TTS
  • strychnine

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