Zeitschrift für vergleichende Physiologie

, Volume 68, Issue 2, pp 117–153 | Cite as

Comparative auditory neurophysiology of neotropical bats employing different echolocation signals

  • Alan D. Grinnell


  1. 1.

    Five species of neotropical bats, which emit echolocation pulses different than those employed by bats previously studied, were investigated in an attempt to find corresponding differences in mechanisms of neural analysis. Evoked potentials were recorded from the posterior colliculi and more peripheral levels in anesthetized specimens.

  2. 2.

    Each species was found to be most sensitive in approximately the same frequency range it uses in its emitted pulses: Chilonycteris rubiginosa at 63 kc/s, Pteronotus suapurensis at 50 kc/s, Saccopteryx bilineata at 42 kc/s, Phyllostomus hastatus at 50 kc/s, and Carollia perspicillata at 80 kc/s. Sensitivity was especially sharply “tuned” in the bats employing predominantly constant frequency pulses (Chilonycteris and Saccopteryx).

  3. 3.

    Chilonycteris, Saccopterys and Pteronotus have prominent evoked potential responses to the end of a tone pip. In Chilonycteris and Saccopteryx these “off”-responses are extremely sharply tuned to a 2–5 kc/s frequency band centered just below the frequency of greatest sensitivity of the “on” response. The presence of an “off”-response appears to be correlated with the use of long, predominantly constant frequency pulses.

  4. 4.

    The rate of recovery of responsiveness following an initial signal varied, being rapid at the level of the colliculus in Phyllostomus and Carollia (100% in 2–3 msec, slight supranormal responsiveness, and no subsequent depression), also rapid in Pteronotus, (but with an unusual degree of facilitation of responsiveness at intervals of 1–2 msec, followed by 5–10 msec of deep depression), and comparatively slow in Chilonycteris and Saccopteryx (full recovery in 10 msec or more).

  5. 5.

    In bats using long orientation pulses which overlap with returning echoes (Chilonycteris and Saccopteryx), the “off”-responses are found to provide a more visible record of the presence of echoes and their time of arrival than do the “on”-responses.

  6. 6.

    Chilonycteris respond to the orientation pulses of other Chilonycteris with prominent “off”-responses, which apparently are evoked by the termination of the constant frequency portion of each pulse rather than the downward FM sweep.

  7. 7.

    Phyllostomus and Chilonycteris are sharply sensitive to changes in signal angle, Pteronotus is moderately so, and Saccopteryx and Carollia are relatively insensitive to angle at the level of the colliculus. In Saccopteryx and Carrollia the auditory nerve response is more sharply sensitive to angular change of the signal.

  8. 8.

    In several species, but most prominently in Pteronotus, large DC potentials, of the same duration as the signal, were recorded in the vicinity of the cochlea and VIII nerve. These potentials were probably “summating potentials” and sometimes showed reversal of polarity with changes in signal frequency.

  9. 9.

    In one preparation (Pteronotus), a DC potential was seen that was apparently contralateral in origin, had a latency 1 msec longer than the ipsilateral “summating potential”, and showed adaptation suggestive of a neural origin. It is suggested that a direct neural pathway between the two ears may exist.

  10. 10.

    It is concluded that species differences in response patterns are at least in part a result of evolutionary adaptation governed by the type of emitted orientation sounds employed.



Auditory Nerve Viii Nerve Subsequent Depression Echolocation Pulse Echolocation Signal 


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  1. Fex, J.: Efferent inhibition in the cochlea related to hair-cell dc activity: study of postsynaptic activity of the crossed olivo-cochlear fibres in the cat. J. acoust. Soc. Amer. 41, 666–676 (1967).Google Scholar
  2. Friend, J. H., Suga, N., Suthers, R. A.: Neural responses in the inferior colliculus of echolocating bats to artifical orientation sounds and echoes. J. cell. Physiol. 67, 319–332 (1966).Google Scholar
  3. Griffin, D. R.: Listening in the dark. New Haven: Yale Univ. Press 1958.Google Scholar
  4. —: Comparative studies of the orientation sounds of bats. Symp. zool. Soc. (Lond.) 7, 61–72 (1962).Google Scholar
  5. —, Novick, A.: Acoustic orientation of neotropical bats. J. exp. Zool. 130, 251–300 (1955).Google Scholar
  6. Grinnell, A. D.: Neurophysiological correlates of echolocation in bats. Ph. D. thesis, Harvard Univ., 1962. Tech. Report No 30, Office of Naval Research. Contr. No 1866 (12) NR-301-219 (1962).Google Scholar
  7. —: The neurophysiology of audition in bats: Intensity and frequency parameters. J. Physiol. (Lond.) 167, 38–66 (1963a).Google Scholar
  8. —: The neurophysiology of audition in bats: Temporal parameters. J. Physiol. (Lond.) 167, 67–96 (1963b).Google Scholar
  9. —: The neurophysiology of audition in bats: Directional localization and binaural interaction. J. Physiol. (Lond.) 167, 97–113 (1963c).Google Scholar
  10. —: The neurophysiology of audition in bats: Resistance to interference. J. Physiol. (Lond.) 167, 114–127 (1963d).Google Scholar
  11. —: Mechanisms of overcoming interference in echolocating animals. In: Animal sonar systems, ed. R-G. Busnel, p. 451–481. Jouy-en-Josas-78, France: Imprimerie Louis-Jean (gab) 1967.Google Scholar
  12. —: The comparative physiology of hearing. Ann. Rev. Physiol. 31, 545–580 (1969).Google Scholar
  13. —, Griffin, D. R.: The sensitivity of echolocation in bats. Biol. Bull. 114, 10–22 (1958).Google Scholar
  14. —, Grinnell, V. S.: Neural correlates of vertical localization by echo-locating bats. J. Physiol. (Lond.) 181, 830–851 (1965).Google Scholar
  15. Grummon, R. A., Novick, A.: Obstacle avoidance in the bat Macrotus mexicanus. Physiol. Zool. 36, 361–369 (1963).Google Scholar
  16. Harrison, J. B.: Temperature effects on response in the auditory system of the little brown bat, Myotis lucifugus. Physiol. Zool. 38, 34–48 (1965).Google Scholar
  17. Henson, O. W., Jr.: The activity and function of the middle ear muscles in echolocating bats. J. Physiol. (Lond.) 180, 871–887 (1965).Google Scholar
  18. —: The perception and analysis of biosonar signals by bats. In: Animal sonar systems, ed. R.-G. Busnel. Jouy-en-Josas-78, France: Laboratoire de Physiologie Acoustique 1967.Google Scholar
  19. Hubel, D. H.: Tungsten microelectrode for recording from single units. Science 125, 549–550 (1967).Google Scholar
  20. Kuhl, W. G., Schodder, R., Schröder, F.-K.: Condenser transmitters with solid dielectrics for airborn ultrasonics. Acustica 4, 519–532 (1954).Google Scholar
  21. McCue, J. J. G.: Ultrasonic instrumentation for research on bats. IRE Internat. Convention Record, 310–315 (1961).Google Scholar
  22. Novick, A.: Orientation in neotropical bats. I. Natalidae and emballonuridae. J. Mammalogy 43, 449–455 (1962).Google Scholar
  23. —: Pulse duration in the echolocation of insects by the bat, Pteronotus. Ergebn. Biol. 26, 21–26 (1963).Google Scholar
  24. —, Vaisnys, J. R.: Echolocation of flying insects by the bat, Chilonycteris parnellii. Biol. Bull. 127, 478–488 (1964).Google Scholar
  25. Pye, A.: The structure of the cochlea in Chiroptera. I. Microchiroptera: Emballonuroidea and Rhinolophoidea. J. Morph. 118, 495–510 (1966a).Google Scholar
  26. —: The structure of the cochlea in Chiroptera. III. Microchiroptera: Phyllostomato idea. J. Morph. 121, 241–254 (1967).Google Scholar
  27. Sandel, T. T., Kiang, N. Y.-S.: Off-responses from the auditory cortex of anesthetized cats: effects of stimulus parameters. Arch. ital. Biol. 99, 105–120 (1961).Google Scholar
  28. Schnitzler, H.-U.: Discrimination of thin wires by flying horseshoe bats (Rhino lophidae). In: Animal sonar systems, ed. R.-G. Busnel, p. 69–87. Jouy-en Josas-78, France: Imprimerie Louis-Jean (gab) 1967.Google Scholar
  29. —: Die Ultraschall-Ortungslaute der Hufeisen-Fledermäuse (Chiroptera-Rhinolophi dae) in verschiedenen Orientierungssituationen. Z. vergl. Physiol. 57, 376–408 (1968).Google Scholar
  30. Suga, N.: Recovery cycles and responses to frequency modulated tone pulses in auditory neurons of echolocating bats. J. Physiol. (Lond.) 175, 50–80 (1964a).Google Scholar
  31. —: Single unit activity in cochlear nucleus and inferior colliculus of echo-locating bats. J. Physiol. (Lond.) 172, 449–474 (1964b).Google Scholar
  32. —: Analysis of frequency modulated sound by auditory neurons of echolocating bats. J. Physiol. (Lond.) 179, 26–53 (1965a).Google Scholar
  33. —: Functional properties of auditory neurons in the cortex of echolocating bats. J. Physiol. (Lond.) 181, 671–700 (1965b).Google Scholar
  34. —: Analysis of frequency-modulated and complex sounds by single auditory neurones of bats. J. Physiol. (Lond.) 198, 51–80 (1968).Google Scholar
  35. Vasiliev, A. G.: A comparative description of the auditory system of bats Vespertilionidae and Rhinolophidae (Electrophysiological data). Dokl. Akad Nauk SSSR 175, 1414–1417 (1967).Google Scholar

Copyright information

© Springer-Verlag 1970

Authors and Affiliations

  • Alan D. Grinnell
    • 1
  1. 1.Department of ZoologyUniversity of CaliforniaLos Angeles

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