Contralateral cochlear destruction mediates protection from monaural loud sound exposures through the crossed olivocochlear bundle

R. Rajan, B. M. Johnstone

Research output: Contribution to journalArticleResearchpeer-review

26 Citations (Scopus)

Abstract

Destruction of the cochlea contralateral to one subsequently exposed to a high intensity acoustic exposure has been shown to reduce the threshold losses caused by the exposure (Rajan and Johnstone, 1983a). The present study tested this manipulation on a wide variety of exposures of varying intensity and duration and found that the amount by which ipsilateral threshold losses were reduced was related to the amount of threshold losses that would have occurred in the absence of the contralateral manipulation. This loss-related protection is also found when the COCB is electrically stimulated during loud sound exposures (Rajan, 1988b; Rajan and Johnstone, 1988b). When the COCB was lesioned at the floor of the fourth ventricle contralateral cochlear destruction no longer protected the test cochlea, confirming that the crossed cochlear protection was exercised through the COCB. The contralateral manipulation did not appear to directly activate the COCB but may have acted in a facilitatory manner on the COCB, allowing activation only when a sufficiently high level exposure was subsequently presented ipsilaterally: a variety of responses at the ipsilateral cochlea and at the brainstem, remeasured after contralateral cochlear destruction and prior to an ipsilateral loud sound exposure, were found to be unaltered, although the TTS to the subsequent exposure was significantly reduced.

Original languageEnglish
Pages (from-to)263-277
Number of pages15
JournalHearing Research
Volume39
Issue number3
DOIs
Publication statusPublished - 6 Jan 1989
Externally publishedYes

Keywords

  • COCB
  • Cochlear destruction
  • Crossed cochlear effects
  • Protection
  • TTS

Cite this

@article{db763a2189464af2ae70f556ab8e7467,
title = "Contralateral cochlear destruction mediates protection from monaural loud sound exposures through the crossed olivocochlear bundle",
abstract = "Destruction of the cochlea contralateral to one subsequently exposed to a high intensity acoustic exposure has been shown to reduce the threshold losses caused by the exposure (Rajan and Johnstone, 1983a). The present study tested this manipulation on a wide variety of exposures of varying intensity and duration and found that the amount by which ipsilateral threshold losses were reduced was related to the amount of threshold losses that would have occurred in the absence of the contralateral manipulation. This loss-related protection is also found when the COCB is electrically stimulated during loud sound exposures (Rajan, 1988b; Rajan and Johnstone, 1988b). When the COCB was lesioned at the floor of the fourth ventricle contralateral cochlear destruction no longer protected the test cochlea, confirming that the crossed cochlear protection was exercised through the COCB. The contralateral manipulation did not appear to directly activate the COCB but may have acted in a facilitatory manner on the COCB, allowing activation only when a sufficiently high level exposure was subsequently presented ipsilaterally: a variety of responses at the ipsilateral cochlea and at the brainstem, remeasured after contralateral cochlear destruction and prior to an ipsilateral loud sound exposure, were found to be unaltered, although the TTS to the subsequent exposure was significantly reduced.",
keywords = "COCB, Cochlear destruction, Crossed cochlear effects, Protection, TTS",
author = "R. Rajan and Johnstone, {B. M.}",
year = "1989",
month = "1",
day = "6",
doi = "10.1016/0378-5955(89)90046-4",
language = "English",
volume = "39",
pages = "263--277",
journal = "Hearing Research",
issn = "0378-5955",
publisher = "Elsevier",
number = "3",

}

Contralateral cochlear destruction mediates protection from monaural loud sound exposures through the crossed olivocochlear bundle. / Rajan, R.; Johnstone, B. M.

In: Hearing Research, Vol. 39, No. 3, 06.01.1989, p. 263-277.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Contralateral cochlear destruction mediates protection from monaural loud sound exposures through the crossed olivocochlear bundle

AU - Rajan, R.

AU - Johnstone, B. M.

PY - 1989/1/6

Y1 - 1989/1/6

N2 - Destruction of the cochlea contralateral to one subsequently exposed to a high intensity acoustic exposure has been shown to reduce the threshold losses caused by the exposure (Rajan and Johnstone, 1983a). The present study tested this manipulation on a wide variety of exposures of varying intensity and duration and found that the amount by which ipsilateral threshold losses were reduced was related to the amount of threshold losses that would have occurred in the absence of the contralateral manipulation. This loss-related protection is also found when the COCB is electrically stimulated during loud sound exposures (Rajan, 1988b; Rajan and Johnstone, 1988b). When the COCB was lesioned at the floor of the fourth ventricle contralateral cochlear destruction no longer protected the test cochlea, confirming that the crossed cochlear protection was exercised through the COCB. The contralateral manipulation did not appear to directly activate the COCB but may have acted in a facilitatory manner on the COCB, allowing activation only when a sufficiently high level exposure was subsequently presented ipsilaterally: a variety of responses at the ipsilateral cochlea and at the brainstem, remeasured after contralateral cochlear destruction and prior to an ipsilateral loud sound exposure, were found to be unaltered, although the TTS to the subsequent exposure was significantly reduced.

AB - Destruction of the cochlea contralateral to one subsequently exposed to a high intensity acoustic exposure has been shown to reduce the threshold losses caused by the exposure (Rajan and Johnstone, 1983a). The present study tested this manipulation on a wide variety of exposures of varying intensity and duration and found that the amount by which ipsilateral threshold losses were reduced was related to the amount of threshold losses that would have occurred in the absence of the contralateral manipulation. This loss-related protection is also found when the COCB is electrically stimulated during loud sound exposures (Rajan, 1988b; Rajan and Johnstone, 1988b). When the COCB was lesioned at the floor of the fourth ventricle contralateral cochlear destruction no longer protected the test cochlea, confirming that the crossed cochlear protection was exercised through the COCB. The contralateral manipulation did not appear to directly activate the COCB but may have acted in a facilitatory manner on the COCB, allowing activation only when a sufficiently high level exposure was subsequently presented ipsilaterally: a variety of responses at the ipsilateral cochlea and at the brainstem, remeasured after contralateral cochlear destruction and prior to an ipsilateral loud sound exposure, were found to be unaltered, although the TTS to the subsequent exposure was significantly reduced.

KW - COCB

KW - Cochlear destruction

KW - Crossed cochlear effects

KW - Protection

KW - TTS

UR - http://www.scopus.com/inward/record.url?scp=0024334272&partnerID=8YFLogxK

U2 - 10.1016/0378-5955(89)90046-4

DO - 10.1016/0378-5955(89)90046-4

M3 - Article

VL - 39

SP - 263

EP - 277

JO - Hearing Research

JF - Hearing Research

SN - 0378-5955

IS - 3

ER -