The contralateral efferent reflex inhibits cochlear compression at matched frequencies

Evidence

For the natural MOCR, the more intense the contralateral stimulus, the greater the amount of efferent inhibition and the more linear the cochlear mechanical response (Hood et al. 1996 ). On the other hand, it seems reasonable that the amount of MOCR inhibition depends on the magnitude of the output from the cochlea rather than on the level of the acoustic stimulus. Inspired by this, we assumed that the instantaneous value of c for any given frequency channel in an MOC processor was inversely related to the output energy, E , from the corresponding channel in the contralateral MOC processor. In other words, the greater the output energy from a given frequency channel in the left-ear processor, the less the compression in the corresponding frequency channel of the right-ear processor, and vice versa (contralateral ‘on-frequency’ inhibition). — Dijk, Pim van, Physiology, Psychoacoustics and…, 1949

2.1 A Bilateral CI Sound Processor Inspired by the Contralateral MOCR To assess the potential effects of the contralateral MOCR in hearing using CIs, pairs of sound processors (one per ear) were implemented where the amount of compression in a given frequency channel of each processor in the pair was either constant (STD strategy) or varied dynamically in time in a manner inspired by the contralateral MOCR (MOC strategy). … For the natural MOCR, the more intense the contralateral stimulus, the greater the amount of efferent inhibition and the more linear the cochlear mechanical response (Hood et al. 1996 ). On the other hand, it seems reasonable that the amount of MOCR inhibition depends on the magnitude of the output from the cochlea rather than on the level of the acoustic stimulus. Inspired by this, we assumed that the instantaneous value of c for any given frequency channel in an MOC processor was inversely related to the output energy, E , from the corresponding channel in the contralateral MOC processor. In other words, the greater the output energy from a given frequency channel in the left-ear processor, the less the compression in the corresponding frequency channel of the right-ear processor, and vice versa (contralateral ‘on-frequency’ inhibition). — Dijk, Pim van, Physiology, Psychoacoustics and…, 1950

Categorization

• QUESTION: Does the natural MOCR truly respond to cochlear output energy rather than acoustic input level? The model assumption rests on plausibility, not direct evidence — worth chasing the underlying physiology.
• DEFINE: Clarifies that MOCR inhibition acts on-frequency between ears, proportional to cochlear output energy rather than raw acoustic level — a physiological mechanism stated as engineering assumption.
• XREF: Connects to the broader MOCR/efferent-reflex literature (Hood 1996, Backus & Guinan 2006) already established in earlier chapters of the efferent system.
• corroborated: 2 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 1949; Dijk, Pim van, Physiology, Psychoacoustics and…, 1950