Frequency tuning of the contralateral medial olivocochlear reflex in humans.

Frequency Tuning of the Contralateral Medial Olivocochlear 5 Reflex in Humans

Frequency tuning of medial-olivocochlear-efferent acoustic reflexes in humans as functions of probe frequency.

The medial-olivocochlear (MOC) acoustic reflex is thought to provide frequency-specific feedback that adjusts the gain of cochlear amplification, but little is known about how frequency specific the reflex actually is. We measured human MOC tuning through changes in stimulus frequency otoacoustic emissions (SFOAEs) from 40-dB-SPL tones at probe frequencies (f(p)s) near 0.5, 1.0, and 4.0 kHz. MO...

Fast and Slow Effects of Medial Olivocochlear Efferent Activity in Humans

BACKGROUND The medial olivocochlear (MOC) pathway modulates basilar membrane motion and auditory nerve activity on both a fast (10-100 ms) and a slow (10-100 s) time scale in guinea pigs. The slow MOC modulation of cochlear activity is postulated to aide in protection against acoustic trauma. However in humans, the existence and functional roles of slow MOC effects remain unexplored. METHODOL...

Type II spiral ganglion afferent neurons drive medial olivocochlear reflex suppression of the cochlear amplifier

The dynamic adjustment of hearing sensitivity and frequency selectivity is mediated by the medial olivocochlear efferent reflex, which suppresses the gain of the 'cochlear amplifier' in each ear. Such efferent feedback is important for promoting discrimination of sounds in background noise, sound localization and protecting the cochleae from acoustic overstimulation. However, the sensory driver...

Medial olivocochlear efferent system in humans studied with amplitude-modulated tones.

Evoked otoacoustic emissions (EOAEs) are assumed to be generated by outer hair cells (OHCs). It is now generally accepted that EOAEs represent a means of functional exploration of the active micromechanical properties of OHCs. Efferent fibers of the medial olivocochlear system (MOCS) are connected along the sides and the bases of OHCs. Some studies have shown that a suppression effect on EOAE a...