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M C Remond

Publications and source records attributed to M C Remond.

13 recordsLinked to original sources
PubMed1987

Variations of cochlear microphonic potential after sectioning efferent fibers to the cochlea.

Cochlear microphonic (CM) potentials were recorded, in guinea pig, with differential electrodes before and after sectioning the medial efferent innervation at the level of the brainstem. Sectioning the crossed part of the medial efferent innervation did not change the CM whatever the frequency or level of stimulation used. Sectioning the medial--crossed and uncrossed--efferent fibers diminished CM amplitude at frequencies above 2 kHz. Thus, the ipsilateral medial efferent tract seems to be involved, through a tonic action, in controlling outer hair cell micromechanics.

Acoustic Stimulation↗
PubMed1986

Efferent tracts and cochlear frequency selectivity.

The cochlear innervation of guinea pigs was sectioned medially in a rostrocaudal direction at the level of the floor of the fourth ventricle, to study the effects of efferent pathways on cochlear microphonic (CM) suppression, the compound action potential (CAP) masking phenomenon, the input-output CAP function, and cochlear frequency selectivity estimated with tuning curves of single auditory nerve fibers. Sectioning reduced CM suppression without having any effect on absolute CM amplitude; it also reduced CAP masking. The input-output CAP function was not changed at intensities below 75 dB, and the single-unit tuning curves recorded before and after nerve sectioning were unaffected. Thus, the crossed efferent tracts (i.e., mainly the medial system) seems to be involved in the masking function itself, rather than one of the mechanisms responsible for high frequency cochlear selectivity.

Acoustic Stimulation↗
PubMed1986

Effects of section of the medial efferent tracts (crossed and uncrossed) on cochlear frequency selectivity.

The cochlear innervation of guinea pigs was sectioned midway between the midline and the external side of the cochlear nucleus, in a rostrocaudal direction at the level of the floor of the fourth ventricle, to study the effects of medial efferent pathways on cochlear frequency selectivity estimated with tuning curves of single auditory nerve fibers. Single-unit tuning curves were affected by this type of efferent sectioning. Thus, the ipsi-lateral efferent system seems to be involved, through a tonic action, in the mechanisms responsible for high frequency cochlea selectivity.

Acoustic Stimulation↗
PubMed1982

A comparison of compound action potential and cochlear microphonic two-tone suppression in the guinea pig.

Cochlear microphonics (CM) and compound action potentials (AP) were recorded simultaneously with differential electrodes in the basal turn of the guinea pig cochlea. When CM two-tone suppression (2TS) curves were compared to AP simultaneous masking curves, good correspondence was observed between CM and AP suppression effects. The relationship between the 10 dB bandwidths of CM and AP 2TS curves remained constant for each animal despite differences between animals resulting from natural variations. Under pathological conditions (acute cochlear hypoxia) both CM and AP two-tone suppression effects were greatly reduced or disappeared. These results can be taken as evidence that CM suppression and AP suppression are the products of a common underlying mechanism.

Action Potentials↗
PubMed1977

Electrocochleographic changes in acoustic neuroma: some experimental findings.

Reversible experimental lesions were produced in the central end of the cochlear nerve at the IAM of guinea pigs by various procedures, including the instillation of KCl (0.1 or 0.01 M). As a result the usual diphasic AP waveforms seen in guinea pigs (when click stimuli are used) were transformed into monophasic, widened negative waves. This change, attributed to a neural block, was reversible, e.g. when the instilled KCl was dispersed by irrigation with normal saline. It is suggested that the widened monophasic negative AP's observed at ECochG in cases of acoustic neuroma or similar lesions, are produced in this way.

Action Potentials↗
PubMedDate not supplied

Relation between the waveform of the cochlear whole nerve action potential and its intensity function.

The whole-nerve action potential (AP) was recorded by intracochlear electrodes in the guinea-pig. As is well known, in normal conditions, the AP elicited by tone bursts displays negative and positive deflections. Inactivation of the central end of the nerve at the internal auditory meatus (IAM), by introduction of a few drops of KC1 solution, or by mechanical pressure, produces a change in the wave shape of AP which is transformed into a single negative deflection. The relation of the amplitude of the monophasic AP to the intensity of the tone burst is monotonic, in contrast to the classical two-slope variation observed in normal conditions. These results are interpreted by the disappearance of a positive component of the response produced at the IAM. The convolution of the monophasic unit AP would explain the monotonic intensity function.

Acoustic Stimulation↗