Afferent innervation of outer and inner hair cells is normal in neonatally de-efferented cats

M. Charles Liberman, Daniel F. O'Grady, Leslie W. Dodds, Joann McGee, Edward J. Walsh

    Research output: Contribution to journalArticlepeer-review

    20 Scopus citations


    It has been hypothesized that normal pruning of exuberant branching of afferent neurons in the developing cochlea is caused by the arrival of the olivocochlear efferent neurons and the resulting competion for synaptic sites on hair cells. This hypothesis was supported by a report that afferent innervation density on mature outer hair cells (OHCs) is elevated in animals de-efferented at birth, before the olivocochlear system reaches the outer hair cell area (Pujol and Carlier [1982] Dev. Brain Res. 3:151-154). In the current study, this claim was evaluated quantitatively at the electron microscopic level in four cats that were de-efferented at birth and allowed to survive for 6-11 months. A semiserial section analysis of 156 OHCs from de-efferented and normal ears showed that, although de-efferentation essentially was complete in all four cases, the number and distribution of afferent terminals on OHCs was indistinguishable from normal, and the morphology of afferent synapses was normal in both the inner hair cell area and the OHC area. Thus, the postnatal presence of an efferent system is not required for the normal development of cochlear afferent innervation, and the synaptic competition hypothesis is not supported. (C) 2000 Wiley-Liss, Inc.

    Original languageEnglish (US)
    Pages (from-to)132-139
    Number of pages8
    JournalJournal of Comparative Neurology
    Issue number1
    StatePublished - Jul 17 2000


    • Cochlea
    • Development
    • Olivocochlear

    ASJC Scopus subject areas

    • Neuroscience(all)


    Dive into the research topics of 'Afferent innervation of outer and inner hair cells is normal in neonatally de-efferented cats'. Together they form a unique fingerprint.

    Cite this