Bilateral cochlear ablation in postnatal rat disrupts development of banded pattern of projections from the dorsal nucleus of the lateral lemniscus to the inferior colliculus

S. R. Franklin, J. K. Brunso-Bechtold, C. K. Henkel

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Axonal projections from the dorsal nucleus of the lateral lemniscus (DNLL) distribute contralaterally in a pattern of banded layers in the central nucleus of the inferior colliculus (IC). The banded pattern of DNLL projections is already in the IC by onset of hearing in postnatal rat pups. Previously, it was shown that unilateral cochlear ablation in neonatal rat pups disrupted the banded pattern in IC for the projections of the DNLL contralateral to the ablation but not those of the DNLL ipsilateral to the ablation. In the present study, bilateral cochlear ablation or sham surgery was performed at postnatal day 9 (P9) after which rat pups were killed at P12 and the brains removed to study axonal projections of the DNLL. A lipophilic carbocyanine dye, 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI), was placed in the dorsal tegmental commissure of Probst to label decussating DNLL axons that end in the central nucleus of the contralateral IC. The distribution of labeled fibers across the central nucleus of the IC was analyzed in digital images by comparing the pattern of labeling with a sine model of periodic distribution of banded layers. In the control group, labeled axons formed a regular pattern of dense banded layers in IC. In the bilateral cochlear ablation group, labeled axons in the IC were distributed diffusely and there was little or no regular pattern of dense bands of axonal labeling. The influence of the cochlea on developing auditory circuits possibly mediated by activity-dependent mechanisms is discussed.

Original languageEnglish
Pages (from-to)346-354
Number of pages9
JournalNeuroscience
Volume154
Issue number1
DOIs
StatePublished - Jun 12 2008

Bibliographical note

Funding Information:
The authors would like to thank Stephanie Evans for her technical support and Dr. John McHaffie for his comments of the text. Supported in part by NIH grant DC004412 and the Mr. and Mrs. A. Tab Williams, Jr. and Family Neuroscience Research and Program Development Endowment.

Keywords

  • DiI
  • auditory
  • carbocyanine dye
  • pattern formation
  • plasticity
  • refinement

ASJC Scopus subject areas

  • Neuroscience (all)

Fingerprint

Dive into the research topics of 'Bilateral cochlear ablation in postnatal rat disrupts development of banded pattern of projections from the dorsal nucleus of the lateral lemniscus to the inferior colliculus'. Together they form a unique fingerprint.

Cite this