Precursor effects on behavioral estimates of frequency selectivity and gain in forward masking.
The experiments presented in this paper explore the hypothesis that cochlear gain is reduced, in a frequency-specific manner, over the course of a sound (called a "precursor") which was designed to activate the medial olivo-cochlear reflex (MOCR). Psychophysical tuning curves (PTCs) and off-frequency growth of masking (GOM) functions were measured with two precursors. The on-frequency precursor condition, which was hypothesized to activate the MOCR at the signal frequency, produced a PTC with a lower best frequency in all subjects consistent with less gain. This same condition produced a GOM function with less gain and an elevated compression breakpoint. The data were analyzed with two models. The gain-reduction model, which assumed a change in the basilar membrane input-output function, was superior at predicting the data relative to a model of additivity of masking.
Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, Indiana 47907, USA. sgjennin@purdue.edu
Skyler G
SG
Jennings
Elizabeth A
EA
Strickland
Michael G
MG
Heinz
D000161:Acoustic Stimulation; D000328:Adult; D000465:Algorithms; D003051:Cochlea / Q000502:physiology; D006309:Hearing / Q000502:physiology; D006801:Humans; D008954:Models, Biological; D009847:Olivary Nucleus / Q000502:physiology; D010470:Perceptual Masking; D011571:Psychoacoustics; D012018:Reflex; D055815:Young Adult