Frequency analysis of sound by the cochlea is the most fundamental property of the auditory system. Despite its importance, the resolution of this frequency analysis in humans remains controversial. The controversy persists because the methods used to estimate tuning in humans are indirect and have not all been independently validated in other species. Some data suggest that human cochlear tuning is considerably sharper than that of laboratory animals, while others suggest little or no difference between species. We show here in a single species (ferret) that behavioral estimates of tuning bandwidths obtained using perceptual masking methods, and objective estimates obtained using otoacoustic emissions, both also employed in humans, agree closely with direct physiological measurements from single auditory-nerve fibers. Combined with human behavioral data, this outcome indicates that the frequency analysis performed by the human cochlea is of significantly higher resolution than found in common laboratory animals. This finding raises important questions about the evolutionary origins of human cochlear tuning, its role in the emergence of speech communication, and the mechanisms underlying our ability to separate and process natural sounds in complex acoustic environments.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Oct 30 2018|
Bibliographical noteFunding Information:
and Brian Moore and an additional reviewer for thorough and constructive comments. Experimental work in ferrets was supported by Medical Research Council intramural funding MC_UU_00010/1 and U135097127. Behavioral experiments in humans were supported by NIH Grant R01DC012262 (to A.J.O. and H.A.K.). C.A.S. was supported by NIH Grant R01 DC003687. C.B. was supported by Natural Sciences and Engineering Research Council of Canada Grant RGPIN-430761-2013.
© 2018 National Academy of Sciences. All rights reserved.
- Auditory nerve
- Cochlear tuning
- Frequency selectivity
- Otoacoustic emissions