The sciatic nerve of the toad Xenopus laevis as a physiological model of the human cochlear nerve

Morse, Robert P. and Evans, Edward F. (2003). The sciatic nerve of the toad Xenopus laevis as a physiological model of the human cochlear nerve. Hearing Research, 182 (1-2), pp. 97-118.

Abstract

The response of single fibres of the human cochlear nerve to electrical stimulation by a cochlear implant has previously been inferred from the response of the cochlear nerve in other mammals. These experiments are hindered by stimulus artefact and the range of stimulus currents used is therefore much less than the perceptual dynamic range (from threshold to discomfort) of human subjects. We have investigated use of the sciatic nerve of the toad Xenopus laevis as a convenient physiological model of the human cochlear nerve. Use of this completely dissected nerve reduces the problems of stimulus artefact whilst maintaining the advantages of a physiological preparation. The validity of the model was assessed by measuring the refractory periods, excitation time-constant, and relative spread of single fibres using microelectrode recording. We have also investigated the response of nerve fibres to sinusoidal stimulation. Based on these measurements, we propose that the sciatic nerve may be a suitable model of the human cochlear nerve if the timescales of stimuli are decreased by a factor of about five to compensate for the slower dynamics of the sciatic nerve and if noise is added to the stimuli to compensate for the lower internal noise of sciatic nerve fibres.

Publication DOI: https://doi.org/10.1016/S0378-5955(03)00187-4
Divisions: Life & Health Sciences > Audiology
Life & Health Sciences
Uncontrolled Keywords: xenopus laevis,cochlear implants,cochlear nerve,cortical synchronization,electric stimulation,electrophysiology,time factors,synapses,sciatic nerve
Published Date: 2003-08
Authors: Morse, Robert P.
Evans, Edward F.

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