Inferred basilar-membrane gain in humans is about 41 dB at 4 kHz

Evidence

An estimate of inferred basilar-membrane gain can be obtained from the data as the difference between onand off-frequency masker level values. The mean gain estimated in the absence of a precursor is 41 dB. The estimated gain (as difference between onand off-frequency masker levels) in the presence of a precursor of different frequencies is shown in Fig. 3 . Maximum gain estimates of about 40 dB indicate little effect of any efferent-mediated cochlear gain reduction, and are associated with precursor frequencies well above and below that of the signal frequency of 4 kHz. Minimum gain estimates of about 20 dB indicate maximal effect of efferent-mediated cochlear gain reduction, and are associated with precursor frequencies close to that of signal frequency of 4 kHz. The estimated 10 dB bandwidth of the efferent-effect filter is 1300 Hz (Q10 of 3.1). — Dijk, Pim van, Physiology, Psychoacoustics and…, 5978

Categorization

• DEFINE: Explains how inferred cochlear gain is derived operationally — as the threshold difference between on- and off-frequency maskers, a psychoacoustic proxy for basilar-membrane amplification.
• QUESTION: A 41 dB inferred human gain at 4 kHz is worth checking against physiologically measured BM gain in other species and other human estimates.