Journal of Comparative Physiology A

, Volume 171, Issue 6, pp 725–734

Labile cochlear tuning in the mustached bat

I. Concomitant shifts in biosonar emission frequency
  • Russell F. Huffman
  • O. W. HensonJr.
Article

DOI: 10.1007/BF00213069

Cite this article as:
Huffman, R.F. & Henson, O.W. J Comp Physiol A (1993) 171: 725. doi:10.1007/BF00213069

Summary

The cochlea of the mustached bat (Pteronotus parnellii) has sharp tuning characteristics and pronounced resonance within a narrow band near the second harmonic, constant frequency (CF2) component of the animal's biosonar signals. That fine frequency discrimination occurs within this narrow band is evident from Doppler-shift compensation, whereby bats in flight lower the frequency of emitted CF2s to maintain returning echoes within this band. This study examined various factors capable of producing shifts in both the cochlear resonance frequency (CRF) and CF2s emitted by stationary bats and bats actively Doppler-shift compensating on a pendulum. Each of three experimental factors shifted the CRF in a reversible manner. Changes in body temperature produced an average CRF shift of 39 ± 18 Hz/°C. The CRF increased with flight by 150 ± 100 Hz and returned to baseline values within 10 min after flight. Contralateral sound exposure produced smaller (100 ± 20 Hz), rapid shifts in the CRF, suggesting that a mechanism different from the temperature- and flight-related shifts was involved. Changes in the CRF induced by temperature and flight were accompanied by shifts in the emitted CF2 of stationary and moving bats. Coupled with a companion study of associated shifts in neural tuning, the concomitant changes in CRF and CF2 provide evidence of cochlear tuning lability in the mustached bat.

Key words

Cochlea Echolocation Resonance Body temperature Pteronotus 

Abbreviations

CF2

second harmonic, constant frequency component of the biosonar signal

CM

cochlear microphonic

CRF

cochlear resonance frequency

Copyright information

© Springer-Verlag 1993

Authors and Affiliations

  • Russell F. Huffman
    • 1
  • O. W. HensonJr.
    • 2
  1. 1.Curriculum in NeurobiologyThe University of North CarolinaChapel HillUSA
  2. 2.Department of Cell Biology and AnatomyThe University of North CarolinaChapel HillUSA
  3. 3.Department of NeurobiologyDuke University Medical CenterDurhamUSA

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