Common substructure in otoacoustic emission spectra of land vertebrates

Geoffrey A. Manley, Christine Köppl, Christopher Bergevin

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Scopus citations


In humans, a similar spectral periodicity is found in all otoacoustic emission types and in threshold fine structure. This may reflect travelling wave phase and reflectance from "structural roughness" in the organ of Corti, or entrainment and suppressive interactions between emissions. To further understand these phenomena, we have examined spontaneous otoacoustic emission (SOAE) spectra in 9 lizard species and the barn owl and find a comparable periodicity. Importantly, the frequency spacing between SOAE peaks was independent of the physical spacing and of the frequency space constants in hearing organs. In 9 lizard species, median spectral gaps lay between 219 and 461 Hz, with no correlation to papillar length (0.3 to 2.1 mm). Similarly in much longer organs: In humans (35 mm), SOAE spectral gaps vary up to 220 Hz at 4 kHz; in the barn owl (11 mm), the median SOAE peak spacing was 395Hz. In the barn owl, a very large space constant between 5 and 10 kHz (5 mm/octave) contrasts with stable SOAE spacing between 1 and 11 kHz. Similar SOAE spectral gaps across all species suggests they represent a basic frequency grating revealing local phase-dependent interactions between active hair cells, a feature not determined by macro-structural anatomy. Emission spectral spacing is independent of cochlear length, of the frequency space constant, of the existence of travelling waves or of a tectorial membrane. Our data suggest that there are greater similarities between frequency selectivity reflected at the level of the hair cells' spontaneous mechanical output (OAEs) than there are at the level of the auditory nerve, where macro-structural anatomy links hair-cell activity differentially to the neural output. Apparently, all hair-cell arrays show a similar frequency substructure not directly replicated in neural tuning.

Original languageEnglish
Title of host publicationMechanics of Hearing
Subtitle of host publicationProtein to Perception - Proceedings of the 12th International Workshop on the Mechanics of Hearing
EditorsDavid P. Corey, K. Domenica Karavitaki
PublisherAmerican Institute of Physics Inc.
ISBN (Electronic)9780735413504
StatePublished - 31 Dec 2015
Externally publishedYes
Event12th International Workshop on the Mechanics of Hearing: Protein to Perception - Cape Sounio, Greece
Duration: 23 Jun 201429 Jun 2014

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Conference12th International Workshop on the Mechanics of Hearing: Protein to Perception
CityCape Sounio


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