Journal of Comparative Physiology A

, Volume 169, Issue 6, pp 719–728

Auditory properties of the superior colliculus in the horseshoe bat, Rhinolophus rouxi

  • Katrin Reimer
Article

DOI: 10.1007/BF00194900

Cite this article as:
Reimer, K. J Comp Physiol A (1991) 169: 719. doi:10.1007/BF00194900

Summary

Auditory response properties were studied in the superior colliculus (SC) of the echolocating horseshoe bat Rhinolophus rouxi, a long CF-FM bat, by the use of stationary, dichotic stimuli.

The most striking finding in the horseshoe bat was an enormous overrepresentation of neurons with best frequencies in the range of the constant frequency component of the species specific echolocation call (72% of the auditory neurons). These neurons had response thresholds as low as 0 dB SPL and were narrowly tuned with Q10 dB — values up to 400, just as in the nuclei of the primary auditory pathway in this species. This overrepresentation may suggest the importance of the superior colliculus in the context of echolocation behavior.

While noise stimuli were not particularly effective, other auditory response properties were similar to those described in other mammals. 65% of the SC neurons in the horseshoe bat responded only to monaural stimulation of one ear, primarily the contralateral one. 32% of the neurons received monaural input from both ears. The proportion of neurons responsive to ipsilateral stimulation (41%) was rather high. Mean response latency was 8.9 ms for contralateral stimulation.

A tonotopic organization is lacking, but high-frequency neurons are less frequent in rostral SC.

Key words

Superior colliculus Bat Audition Echolocation 

Abbreviations

CF

constant frequency component of echolocation call;

>CF

frequencies above range of CF-component

FM

frequency modulated component of echolocation call

<FM

frequencies below range of FM-component

RF

resting frequency of an individual bat

Rh.r.

Rhinolophus rouxi

SC

superior colliculus

Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • Katrin Reimer
    • 1
  1. 1.Zoologisches Institut der Universität München, Luisenstraße 14München 2Germany
  2. 2.Abteilung für Vergleichende Neurobiologie, Universität UlmUlmGermany

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