Journal article
Electrically evoked single-fiber action potentials from cat: responses to monopolar, monophasic stimulation
Hearing research, Vol.130(1), pp.197-218
04/01/1999
DOI: 10.1016/S0378-5955(99)00012-X
PMID: 10320109
Abstract
We recorded action potentials from single auditory-nerve fibers of cats using monophasic current pulses delivered by a monopolar intracochlear electrode. These simple stimuli provided a means of investigating basic properties and hypotheses of electrical excitation. Standard micropipette recording techniques were used. Responses to anodic (positive) and cathodic (negative) stimulus pulses were recorded separately to evaluate stimulus polarity effects. Mean spike (action potential) latency was polarity dependent, with greater latencies for cathodic stimulation. Threshold stimulus level was also polarity dependent, with relatively lower cathodic thresholds. Both effects are consistent with trends reported in the compound action potential. Variability in single-fiber latency (i.e., jitter) was dependent upon stimulus polarity. In contrast, the slope of single-fiber input-output functions failed to show a clear polarity dependence, although such trends have been seen in the compound action potential data. We also observed a relatively greater degree of adaptation over time with anodic stimulation. Bimodal post-stimulus-time histograms were recorded in a small number (2%) of fibers, supporting the hypothesis that both the peripheral (dendritic) and central axonal processes are excitable with the same stimulus polarity, in a limited number of cases. This observation, together with analyses of interactions among measures of latency, threshold, and jitter, is consistent with the hypothesis that, with monopolar intracochlear stimulation, most fibers are stimulated at axonal (modiolar) sites and a minority of fibers nearest the electrode are stimulable at their peripheral processes.
Details
- Title: Subtitle
- Electrically evoked single-fiber action potentials from cat: responses to monopolar, monophasic stimulation
- Creators
- Charles A. Miller - Department of Otolaryngology, Head and Neck Surgery, 200 Hawkins Drive, C-21 GH, University of Iowa, Iowa City, IA 52242, USAPaul J. Abbas - University of IowaBarbara K. Robinson - University of IowaJay T. Rubinstein - University of IowaAkihiro J. Matsuoka - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Hearing research, Vol.130(1), pp.197-218
- Publisher
- Elsevier B.V
- DOI
- 10.1016/S0378-5955(99)00012-X
- PMID
- 10320109
- ISSN
- 0378-5955
- eISSN
- 1878-5891
- Language
- English
- Date published
- 04/01/1999
- Academic Unit
- Otolaryngology
- Record Identifier
- 9984383892802771
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