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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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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