Electrophysiological Experiments on Hearing in Odontocetes

  • Sam H. Ridgway
Part of the NATO Advanced Study Institutes Series book series (volume 28)


Although electrophysiological techniques have not been extensively employed in the study of cetacean hearing, there are more than a dozen significant studies that will be briefly reviewed in this paper. These techniques have been useful for measuring hearing thresholds by evoked responses and classical conditioning (several animals each of Phocoena and Tursiops). The auditory cortex has been located at the dorsum of the cerebral hemisphere only 1.5 to 3.0 cm lateral to the midline and adjacent to visual and somatosensory cortex. The midbrain auditory structures of dolphins are specialized for ultrabrief, ultrasonic, fast-rising, closely spaced sounds like echolocation clicks, and temporal resolution is rapid. Frequency-modulated tones produce maximum responses both at midbrain locations and at cortical recording sites, suggesting the importance of such signals to the animals. Methods and equipment are now available for broader application of electrophysiological techniques without expenditure of valuable animals. These techniques can contribute further insight concerning how odontocetes process sound and what characteristics of the acoustic information package are most important to the animal.


Auditory Cortex Inferior Colliculus Bottlenose Dolphin Galvanic Skin Response Electrophysiological Experiment 


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  1. Bullock, T. H, Grinnell, A. D., Ikezono, E., Kamedo, K., Katsuki, Y., Nomoto, M., Sato, O., Suga, N., and Yanagisawa, K., 1968, Electrophysiological studies of central auditory mechanism in cetaceans, Zeitschrift für vergleichende Phys. iologie, 59:117.Google Scholar
  2. Bullock, T. H., and Gurevich, V. S., 1979, Soviet literature on the nervous system and psychobiology of cetaceans, International Review of Neurobiology, (in press).Google Scholar
  3. Bullock, T. H., and Ridgway, S. H., 1971, Evoked potentials in the auditory system of alert porpoises (Cetacea) and sea lions (Pinnipedia) to their own and to artificial sounds, Proc. Int. Un. Physiol., IX:89.Google Scholar
  4. Bullock, T. H., and Ridgway, S. H., 1972a, Neurophysiological findings relevant to echolocation in marine mammals, in: “Animal Orientation and Navigation”, S. R. Galler, K. Schmidt-Koenig, G. J. Jacobs, R. E. Belleville, eds., NASA, U.S. Govn’t Printing Off., Washington, D.C.Google Scholar
  5. Bullock, T. H. and Ridgway, S. H., 1972b, Evoked potentials in the central auditory system of alert porpoises to their own and artificial sounds, J. Neurobiol., 3:79.CrossRefGoogle Scholar
  6. Galambos, R. and Hecox, K, 1977, Clinical applications of the brain stem auditory evoked potentials in man,”Psychopharmacology Correlates of Evoked Potentials”, Vol. 2, J. E. Desmedt, ed., Krager, Basel.Google Scholar
  7. Johnson, C. S., 1966, Auditory thresholds of the bottlenosed porpoise (Tursiops truncatus Montagu), N.O.T.S. TP 4178.Google Scholar
  8. Ladygina, T. F., and Supin, A. Y., 1970, The acoustic projection in the dolphin cerebral cortex, Fiziol. Zh. SSSR im. I. M. Sechenova, 56:1554.PubMedGoogle Scholar
  9. Ladygina, T. F., and Supin, A. Y., 1977, Localization of sensory projection zones in the cerebral cortex of the bottlenosed dolphin, Tursiops truncatus, Zh. Evolyutsionnoy Biokhimii I Fiziol.Google Scholar
  10. Lende, R. A., and Akdikmen, S., 1968, Motor field in the cerebral cortex of the bottlenosed dolphin, J. Neurosurgery, 29:495.CrossRefGoogle Scholar
  11. Lende, R. A., and W. I. Welker, 1972, An unusual sensory area in the cerebral neocortex of the bottlenose dolphin, Tursiops truncatus, Brain Research, 45:555.CrossRefGoogle Scholar
  12. McCormick, J. G., Wever, E. G., Palin, J., and Ridgway, S. H., 1970, Sound conduction in the dolphin ear, J. Acoust. Soc. Amer., 48:1418.CrossRefGoogle Scholar
  13. Norris, K. S., 1964, Some problems of echolocation in cetaceans, in: “Marine Bio-Acoustics”, W. N. Tavolga, ed., Pergamon Press, New York.Google Scholar
  14. Popov, V. V., and Supin, A. Y., 1976, Determination of the hearing characteristics of dolphins by measuring induced potentials, Fiziol. Zh. SSSR im. I. M. Sechenova, 62:550.PubMedGoogle Scholar
  15. Popov, V. V., and Supin, A. Y., 1976, Responses of the dolphin auditory cortex to complex acoustic stimuli, Fiziol. Zh. SSSR im. I. M. Sechenova, 62:1780.PubMedGoogle Scholar
  16. Popov, V. V., and Supin, A. Y., 1978, Electrophysiological studies of the auditory system of the Tursiops truncatus, in: “Morskiye Mlekopitayushchiye. Resul’taty i Metody Issledovaniya”, Izdatel’stvo Nauka, Moscow.Google Scholar
  17. Ridgway, S. H., Carder, D. A., Green, R. F., Gaunt, A. S., Gaunt, S. L. L., and Evans, W. E., 1979, Electromyographic and pressure events in the nasolaryngeal system of dolphins during sound production, this volume.Google Scholar
  18. Ridgway, S. H., and McCormick, J. G., 1967, Anesthetization of porpoises for major surgery, Science, 158:510.PubMedCrossRefGoogle Scholar
  19. Ridgway, S. H., and Seeley, R. L., 1979, Auditory evoked responses of the dolphin cortex to four different sound stimuli, in preparation.Google Scholar
  20. Seeley, R. L., Flanigan, W. F., and Ridgway, S. H., 1976, A technique for rapidly assessing the hearing of the bottlenosed porpoise Tursiops truncatus, Naval Undersea Center TP 552, San Diego, California.Google Scholar
  21. Sukhoruchenko, M. N., 1971, Upper limit of hearing of dolphins with reference to frequency, Tr. Akust. Inst. Moscow, 17:54.Google Scholar
  22. Sukhoruchenko, M. N. 1973, Frequency discrimination of dolphin (Phocoena phocoena), Fiziol. Zh. SSSR im. I. M. Sechenova, 59:1205.PubMedGoogle Scholar
  23. Supin, A. Y. and Sukhoruchenko, M. N., 1970, The determination of auditory thresholds in Phocoena phocoena by the method of skin galvanic reaction, Tr. Akust. Inst. Moscow, 12:194.Google Scholar
  24. Supin, A. Y., and Sukhoruchenko, M. N., 1974, Characteristics of acoustic analyzer of the harbor porpoise Phocoena phocoena, in: “Morfologiya, Fiziologiya i Akustika Morshkikh Mlekopitayushchikh”, V. Y. Sokolov, ed., Izdatel’stvo Nauka, Moscow.Google Scholar
  25. Supin, A. Y., Mukhametov, L. M., Ladygina, R. F., Popov, V. V., Mass, A. M., and Polyakova, I. G., 1978,“Electrophysiological Studies of the Dolphin’s Brain”, V. E. Sokolov, ed., Izdatel’stvo Nauka, Moscow.Google Scholar
  26. Thompson, R. K. R., and Herman, L. M., 1975, Underwater frequency discrimination in the bottlenose dolphin (1–140 kHz) and in human (1–8 kHz), J. Acoust. Soc. Amer., 57:943.CrossRefGoogle Scholar
  27. Voronov, V. A., and Stosman, I. M., 1977, Frequency-threshold characteristics of subcortical elements of the auditory analyzer of the Phocoena phocoena porpoise, Zh. Evolyutsionnoy Biokhimii I Fiziol., 6:719.Google Scholar
  28. Zanin, A. V., Bibikov, N. G., Vodyanaya, E. G., 1978, Evoked potentials of the Tursiops under the stimulation with short sound signals, in: “VII-aya Vsesoyuznayz Konferentsiyz po Morskim Mlekopitayushchim”, Simpheropol’.Google Scholar

Copyright information

© Plenum Press, New York 1980

Authors and Affiliations

  • Sam H. Ridgway
    • 1
  1. 1.Naval Ocean Systems CenterSan DiegoUSA

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