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Ventral cochlear nucleus responses to contralateral sound are mediated by commissural and olivocochlear pathways.

Publication ,  Journal Article
Bledsoe, SC; Koehler, S; Tucci, DL; Zhou, J; Le Prell, C; Shore, SE
Published in: J Neurophysiol
August 2009

In the normal guinea pig, contralateral sound inhibits more than a third of ventral cochlear nucleus (VCN) neurons but excites <4% of these neurons. However, unilateral conductive hearing loss (CHL) and cochlear ablation (CA) result in a major enhancement of contralateral excitation. The response properties of the contralateral excitation produced by CHL and CA are similar, suggesting similar pathways are involved for both types of hearing loss. Here we used the neurotoxin melittin to test the hypothesis that this "compensatory" contralateral excitation is mediated either by direct glutamatergic CN-commissural projections or by cholinergic neurons of the olivocochlear bundle (OCB) that send collaterals to the VCN. Unit responses were recorded from the left VCN of anesthetized, unilaterally deafened guinea pigs (CHL via ossicular disruption, or CA via mechanical destruction). Neural responses were obtained with 16-channel electrodes to enable simultaneous data collection from a large number of single- and multiunits in response to ipsi- and contralateral tone burst and noise stimuli. Lesions of each pathway had differential effects on the contralateral excitation. We conclude that contralateral excitation has a fast and a slow component. The fast excitation is likely mediated by glutamatergic neurons located in medial regions of VCN that send their commissural axons to the other CN via the dorsal/intermediate acoustic striae. The slow component is likely mediated by the OCB collateral projections to the CN. Commissural neurons that leave the CN via the trapezoid body are an additional source of fast, contralateral excitation.

Duke Scholars

Published In

J Neurophysiol

DOI

ISSN

0022-3077

Publication Date

August 2009

Volume

102

Issue

2

Start / End Page

886 / 900

Location

United States

Related Subject Headings

  • Tympanic Membrane Perforation
  • Neurotoxins
  • Neurons
  • Neurology & Neurosurgery
  • Microelectrodes
  • Melitten
  • Malleus
  • Hearing Loss, Sensorineural
  • Guinea Pigs
  • Glutamic Acid
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Bledsoe, S. C., Koehler, S., Tucci, D. L., Zhou, J., Le Prell, C., & Shore, S. E. (2009). Ventral cochlear nucleus responses to contralateral sound are mediated by commissural and olivocochlear pathways. J Neurophysiol, 102(2), 886–900. https://doi.org/10.1152/jn.91003.2008
Bledsoe, Sanford C., Seth Koehler, Debara L. Tucci, Jianxun Zhou, Colleen Le Prell, and Susan E. Shore. “Ventral cochlear nucleus responses to contralateral sound are mediated by commissural and olivocochlear pathways.J Neurophysiol 102, no. 2 (August 2009): 886–900. https://doi.org/10.1152/jn.91003.2008.
Bledsoe SC, Koehler S, Tucci DL, Zhou J, Le Prell C, Shore SE. Ventral cochlear nucleus responses to contralateral sound are mediated by commissural and olivocochlear pathways. J Neurophysiol. 2009 Aug;102(2):886–900.
Bledsoe, Sanford C., et al. “Ventral cochlear nucleus responses to contralateral sound are mediated by commissural and olivocochlear pathways.J Neurophysiol, vol. 102, no. 2, Aug. 2009, pp. 886–900. Pubmed, doi:10.1152/jn.91003.2008.
Bledsoe SC, Koehler S, Tucci DL, Zhou J, Le Prell C, Shore SE. Ventral cochlear nucleus responses to contralateral sound are mediated by commissural and olivocochlear pathways. J Neurophysiol. 2009 Aug;102(2):886–900.

Published In

J Neurophysiol

DOI

ISSN

0022-3077

Publication Date

August 2009

Volume

102

Issue

2

Start / End Page

886 / 900

Location

United States

Related Subject Headings

  • Tympanic Membrane Perforation
  • Neurotoxins
  • Neurons
  • Neurology & Neurosurgery
  • Microelectrodes
  • Melitten
  • Malleus
  • Hearing Loss, Sensorineural
  • Guinea Pigs
  • Glutamic Acid