Slow variation of the amplitude of acoustic distortion at f2-f1 in awake rabbits.
A slow, reversible change in f2-f1 distortion-product otoacoustic emission (DPOAE) amplitude in the absence of correlated changes in 2f1-f2 DPOAE amplitude has been recently reported in anesthetized guinea pigs and gerbils, suggesting a dissociation in the generation of these two emissions. It was proposed that the observed changes in f2-f1 amplitude may represent an efferent influence on cochlear mechanics [Brown, A.M., Hear. Res., 34, 27-38, 1988]. In the present study, a search was made for similar changes in f2-f1 amplitude in awake rabbits. Qualitatively similar variations in f2-f1 DPOAE amplitude, in the absence of 2f1-f2 amplitude variations, were found in all ears tested, supporting the hypothesis of a dissociation of the generators of the two DPOAEs. The behavior of the f2-f1 DPOAE amplitude changes observed here, however, provided no evidence of an efferent involvement.
Whitehead
M L
ML
Department of Otorhinolaryngology and Communicative Sciences, Baylor College of Medicine, Houston, Texas 77030.
Lonsbury-Martin
B L
BL
Martin
G K
GK
D000161:Acoustic Stimulation; D000818:Animals; D001306:Auditory Pathways / Q000502:physiology; D003051:Cochlea / Q000294:innervation / Q000502:physiology; D004423:Ear / Q000502:physiology*; D004525:Efferent Pathways / Q000502:physiology; D006309:Hearing / Q000502:physiology; D009847:Olivary Nucleus / Q000502:physiology; D011817:Rabbits