Single unit clues to cochlear mechanisms

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Abstract

In recent years studies on isolated hair cells have suggested that there is an inherent tuning of hair cells determined by their mechanical and electrical properties. However, tuning for mammalian cochleas appears to be much more complicated since there are typically two types of receptor cells (inner and outer hair cells) imbedded in a highly organized framework of supporting cells, membranes and fluids. The major neural output of the cochlea can be monitored by recording the activity of myelinated axons of spiral ganglion cells, not only under normal conditions, but also when the discharge patterns are altered by ototoxic drugs, acoustic trauma or olivocochlear bundle stimulation. A model system with two excitatory influences, one sharply tuned and highly sensitive, and a second, broadly tuned and relatively insensitive, can account for much of the existing data. Results from single-neuron marking studies support the notion that these two influences probably involve interactions between inner and outer hair cells. More global influences such as the endocochlear potential also can act on auditory-nerve fibers through the hair-cell systems. Thus, the inherent frequency selectivity of the receptor cell is only one of many factors that determine the tuning of mammalian auditory-nerve fibers.

References (39)

  • P. Dallos

    Peripheral mechanisms of hearing

  • P. Dallos

    Response characteristics of mammalian cochlear hair cells

    J. Neurosci.

    (1985)
  • P. Dallos et al.

    Production of cochlear potentials by inner and outer hair cells

    J. Acoust. Soc. Am.

    (1976)
  • E.F. Evans et al.

    Reversible effects of cyanide and furosemide on the tuning of single cochlear nerve fibers

    J. Physiol. (London)

    (1974)
  • M.L. Gifford

    The effect of stimulation of the crossed olivocochlear bundle on tuning curves and the response phase of single auditory nerve fibers

  • M.L. Gifford et al.

    Effects of crossedolivocochlear-bundle stimulation of cat auditory nerve fiber responses to tones

    J. Acoust. Soc. Am.

    (1983)
  • J.J. Guinan et al.

    Differential olivocochlear projections from lateral vs. medial zones of the superior olivary complex

    J. Comp Neurol.

    (1983)
  • T. Hoshino

    Attachment of the inner sensory hairs to the tectorial membrane. A scanning electron microscopic study

    Ann. Otol. Rhinol. Laryngol.

    (1976)
  • A.J. Hudspeth

    Extracellular current flow and the site of transduction by vertebrate hair cells

    J. Neurosci.

    (1982)
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