Further Studies On the Peripheral Auditory System of ‘CF-FM’ Bats Specialized for Fine Frequency Analysis of Doppler-Shifted Echoes
Open Access
- 1 June 1977
- journal article
- research article
- Published by The Company of Biologists in Journal of Experimental Biology
- Vol. 69 (1) , 207-232
- https://doi.org/10.1242/jeb.69.1.207
Abstract
In the mustache bat (Pteronotus parnellii rubiginosus), the cochlear microphonic (CM) recorded from the round window was sharply tuned at 61 kHz and showed a prminent transient response to a tone burst at about 61 kHz, (i.e., its amplitude increased exponentially at the onset of the stimulus and decreased at its cessation). In terms of the time constant (1.1 .+-. 0.3 ms) and the resonance frequency (61.1 .+-. 0.43 kHz) of this transient response, the Q of this system, assumed to correspond to a 2nd-order filter, was 204 .+-. 57. Peripheral neurons sensitive to 61 kHz had a very sharp excitatory area (or tuning curve). The Q of a tuning curve markedly increased with the rise in best frequency up to 61 kHz and decreased beyond 61 kHz. The Q value of a single neuron with best frequencies between 60.76-61.75 kHz was 210 .+-. 89. If the assumption that the CM is directly related to the mechanical motion of the basilar membrane is correct, the very sharp tuning curves of single neurons at about 61 kHz could be simply due to the mechanical tuning of the basilar membrane. Since this animal predominantly uses a 61 kHz sound for echolocation and peripheral auditory neurons show a low threshold and extremely sharp tuning at about 61 kHz, its peripheral auditory system is specialized for the reception and fine-frequency analysis of the principle component of orientation sounds and echoes. Sharply tuned neurons can code a frequency modulation as small as 0.01%, so that the wing beat of an insect would be easily coded. Unlike the CM, N1 was tuned at 64 kHz. This difference in best frequency is simply due to the properties of a sharply tuned resonator and N1, and not due to a mechanism comparable to lateral inhibition.This publication has 31 references indexed in Scilit:
- Localized cochlear microphonics recorded from the spiral laminaThe Journal of the Acoustical Society of America, 1976
- Response of the Doppler echolocation system in the bat, Rhinolophus ferrumequinumThe Journal of the Acoustical Society of America, 1974
- Auditory frequency discrimination in vertebratesThe Journal of the Acoustical Society of America, 1974
- Detection of insect wing beats by the bat, Pteronotus parnelliiThe Journal of the Acoustical Society of America, 1974
- Cochlear mechanics, nonlinearities, and cochlear potentialsThe Journal of the Acoustical Society of America, 1974
- Basilar Membrane Vibration Data and Their Relation to Theories of Frequency AnalysisPublished by Springer Nature ,1974
- High frequency peaks in the cochlear microphonic response of rodentsJournal of Comparative Physiology A, 1973
- AN INVESTIGATION OF POST-MORTEM COCHLEAR MECHANICS USING THE MÖSSBAUER EFFECTPublished by Elsevier ,1973
- Cochlear Microphonic Audiograms in the "Pure Tone" Bat Chilonycteris parnellii parnelliiScience, 1972
- The structure of the cochlea in chiroptera. III. Microchiroptera: PhyllostomatoideaJournal of Morphology, 1967