This book is actually a product of efforts of many people, not only of the authors. W ide investigations of marine mammals began in Russia (that time, in the former Soviet Union) in the 1960s when a few teams of enthusiasts founded in captivity experimental stations intended for keeping dolphins and seals and for performing experimental studies of these fascinating animals. It was a time when attention of many people throughout the world was attracted to dolphins and other marine mammals due to appearance of oceanariums and dolphinariums, which demonstrated unique capabilities of these animals. So scientists in many countries concentrated on studies of them. There was much to learn about the morphology, physiology, and psychology of marine mammals, and investigators spending their time and efforts on studies in this field were rewarded by a number of surprising findings. The authors of this book represent one of such research teams focused on the neuro- and sensory physiology of marine mammals. A few decades of studies naturally resulted in the idea to summarize in a book both the results of these studies and a large body of data in adjacent fields. Our goal was to synthesize the many research findings and the present knowledge on sensory capabilities and mechanisms of sensory systems of aquatic mammals. We realize, however, that the appearance of this book was made possible due to the help and assistance of many colleagues.

Inhaltsangabe1. Intruduction.- 1.1. General.- 1.2. Aquatic Mammals as Subjects of Experimental Studies.- 1.3. The Physical Properties of Water as a Sensory Medium.- 1.3.1. Acoustics.- 1.3.2. Optics.- 1.4. Psychophysical Measurement Procedures.- 1.4.1. The Operant Conditioning Method.- 1.4.2. Conditioned Reflex.- 1.4.3. The Statistical Basis for Threshold Evaluation.- 1.4.4. Data-Collection Procedures.- 2. Hearing in Cataceans.- 2.1. Ear Morphology.- 2.1.1. Outer Ear and Middle Ear.- 2.1.2. Inner Ear and Peripheral Neurons.- 2.2. Auditory Evoked Potentials in Cetaceans.- 2.2.1. Intracranial Evoked Potentials.- 2.2.2. Auditory Brainstem Responses (ABR).- 2.2.3. Noninvasively Recorded Cortical Evoked Responses.- 2.2.4. Rhythmic Evoked Potentials.- 2.2.5. Contribution of Various Frequency Bands to ABR.- 2.3. Evoked-Potential Procedures in Hearing Measurements.- 2.3.1. ABR Threshold Measurements.- 2.3.2. EFR and RFR Threshold Measurements.- 2.4. Hearing Sensitivity and Frequency Range.- 2.4.1. Psychophysical Data.- 2.4.2. Evoked-Potential Data.- 2.5. Temporal Resolution.- 2.5.1. Psychophysical Studies.- 2.5.2. Dependence of ABR on Stimulus Duration.- 2.5.3. ABR Recovery at Double-Click Stimulation.- 2.5.4. Gap-in-Noise Detection Measurements.- 2.5.5. Derivation of the Temporal Transfer Function of the Auditory System.- 2.5.6. Rhythmic Amplitude-Modulation Test and Modulation Transfer Function.- 2.5.7. Rhythmic Click Test.- 2.6. Frequency Tuning.- 2.6.1. Critical Ratios and Critical Bands.- 2.6.2. Tuning Curves.- 2.6.3. Notch-Noise Masking.- 2.6.4. Frequency-Discrimination Limens.- 2.6.5. Frequency Resolving Power.- 2.7. Sound-Intensity Discrimination.- 2.8. Directional Sensitivity, Spatial, and Binaural Hearing.- 2.8.1. Psychophysical Studies.- 2.8.2. Directional Sensitivity: Evoked-Potential Studies.- 2.8.3. Binaural Hearing: Evoked-Potential Studies.- 2.9. Frequency-Temporal and Frequency-Spatial Interactions.- 2.9.1. Temporal Interaction of Frequency-Colored Sound Pulses.- 2.9.2. Paradoxical Lateral Suppression.- 2.9.3. Interaction of Directional and Frequency Sensitivity.- 2.10. Sound-Conduction Pathways.- 2.11. Central Representation of the Auditory System.- 2.12. Implements to Echolocation.- 2.12.1. Hearing Frequency Range.- 2.12.2. Frequency Tuning and Temporal Resolution.- 2.12.3. Recovery Functions as a Basis of Invariant Perception of Echo Signals.- 2.12.4. Rippled Spectrum Resolution and Echolocation.- 2.12.5. Frequency-Temporal Interactions.- 2.12.6. Spatial Resolution.- 2.13. Summary.- 3. Hearing in Pinnipeds and Sirenians.- 3.1. Hearing in Pinnipeds.- 3.1.1. Ear Anatomy.- 3.1.2. Hearing Sensitivity and Frequency Range.- 3.1.3. Temporal Processing.- 3.1.4. Frequency Tuning.- 3.1.5. Intensity Discrimination.- 3.1.6. Directional Hearing.- 3.1.7. Auditory Representation in the Cerebral Cortex.- 3.1.8. Hearing Adaptation to Amphibious Lifestyle.- 3.2. Hearing in Sirenians.- 3.2.1. Ear Morp1hology.- 3.2.2. Psychophysical Audiogram.- 3.2.3. Evoked-Potential Data.- 3.3. Summary.- 4. Vision in Aquatic Mammals.- 4.1. Vision in Cetaceans.- 4.1.1. Eye Morphology.- 4.1.2. Visual Abilities of Cetaceans: Psychophysical Studies.- 4.1.3. Topographic Distribution of Retinal Ganglion Cells.- 4.1.4. Visual Projections to the Cerebral Cortex.- 4.2. Vision in Pinnipeds.- 4.2.1. Eye Morphology.- 4.2.2. Visual Abilities of Pinnipeds.- 4.2.3. Topographic Distribution of Retinal Ganglion Cells and Retinal Resolution.- 4.2.4. Visual Projections to the Cerebral Cortex.- 4.3. Vision in Sirenians.- 4.3.1. Eye Anatomy and Retinal Structure.- 4.3.2. Psychophysical Studies.- 4.3.3. Topographic Distribution of Ganglion Cells and Retinal Resolution.- 4.4. Summary.- 5. Somatic Sense in Aquatic Mammals.- 5.1. Somatic Sense in Cetaceans.- 5.2. Somatic Sense in Pinnipeds.- 5.2.1. Morphological and Psychophysical Data.- 5.2.2. Somatosensory Projections to the Cerebral Cortex.- 5.2.2. Tactile Sensitivity of Vibrissae.- 5.3. Summary.- References.

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