Document Detail

The development of a single frequency place in the mammalian cochlea: the cochlear resonance in the mustached bat Pteronotus parnellii.
MedLine Citation:
PMID:  14645493     Owner:  NLM     Status:  MEDLINE    
Cochlear microphonic potentials (CMs) were recorded from the sharply tuned, strongly resonant auditory foveae of 1- to 5-week-old mustached bats that were anesthetized with Rompun and Ketavet. The fovea processes Doppler-shifted echo responses of the constant-frequency component of echolocation calls. During development, the frequency and tuning sharpness of the cochlear resonance increases, and CM ringing persists for longer after the tone. CM is relatively insensitive at tone onset and grows linearly with increased stimulus level. During the tone, the CM is more sensitive and grows compressively with increased stimulus level and phase leads onset CM by 90 degrees for frequencies below the resonance. CM during the ringing is also sensitive and compressive and phase leads onset CM by 180 degrees below the resonance and lags it by 180 degrees above the resonance. Throughout postnatal development, CMs measured during the tone and in the ringing increase both in sensitivity and compression. The cochlear resonance appears to be attributable to interaction between two oscillators. The more broadly tuned oscillator dominates the onset response, and the narrowly tuned oscillator dominates the ringing. Early in development, mechanical coupling between the oscillators results in a relatively broadly tuned system with several frequency modes in the CM at tone onset and in the CM ringing. Beating occurs between the resonance and the stimulus response during the tone and between two components of the narrowly tuned oscillator at tone offset. At maturity, the CM has three modes for frequencies within 10 kHz of the resonance at tone onset and a single, sharply tuned mode in the ringing.
Ian J Russell; Markus Drexl; Elisabeth Foeller; Marianne Vater; Manfred Kössl
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  23     ISSN:  1529-2401     ISO Abbreviation:  J. Neurosci.     Publication Date:  2003 Nov 
Date Detail:
Created Date:  2003-12-03     Completed Date:  2003-12-16     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  10971-81     Citation Subset:  IM    
School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, United Kingdom.
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MeSH Terms
Acoustic Stimulation / methods
Age Factors
Biological Clocks / physiology
Chiroptera / physiology*
Cochlea / growth & development*,  physiology*
Cochlear Microphonic Potentials / physiology*
Echolocation / physiology*
Pitch Discrimination / physiology

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