Sensory Systems of Primates

Primates are avid explorers that utilize a variety of sensory clues from the environment. The special senses of olfaction, audition, and particu­ larly vision are thus of paramount significance in the evolution and adaptive radiation of the primates. It was with this in mind that this volume was planned to present some recent research advances. The chapter on olfactory communication among primates affords new insights concerning a sense which, though primatologists have generally relegated it to a minor role, is of considerable significance in the primates. The chapters on the auditory system are organized to stress three aspects: the receptive organ, the neural pathways, and the role of audition in primate communication. The visual system, the dominant special sense of primates, is analyzed with respect to two regions of the brain, namely, the organization of the superior colliculus and the visual cortex. Finally, the chapter on endocasts in the study of primate brain evolution will alert neurobiologists to the relevant information that can be unearthed from fossils embedded in the terrane. I wish to thank the publishers, and especially Miss Phyllis Straw and Mr. Seymour Weingarten, for their support, patience, guidance, and professional assistance.

Contenu

1. Structural Organization and Communicatory Functions of Olfaction in Nonhuman Primates.- I. Introduction.- II. Structural Organization.- A. The Nasal Cavity and the Extent of Olfactory Surface.- B. Olfactory Epithelium.- C. Vomeronasal (Jacobson's) Organ and Epithelium, and the Accessory Olfactory Bulb.- D. Olfactory Bulb.- E. Secondary and Higher Projections of the Olfactory Bulb.- III. Communicatory Functions of Olfactory Signals.- A. Species Identity.- B. Sexual Identity.- C. Identification of Reproductive Condition.- D. Individual Identity.- E. Identification of Emotional and Social Condition.- IV. References.- 2. Physical and Physiological Principles Controlling Auditory Sensitivity in Primates.- I. Introduction.- II. The Ear as an Early Warning Device.- III. Sensitivity of Detection.- A. Minimization of Transmission Losses.- B. Increase in Energy Collection.- C. Sensitivity of Biological Mechanodetectors.- IV. Directional Reception of Sound.- A. Causes of Interaural Intensity Differences.- B. Causes of Interaural Time Differences.- C. Detection of Sound in the Presence of Noise.- V. Brownian Noise.- VI. Improvement in Sensitivity of Detection by Reduction of Noise.- VII. The Effect of Narrow-Band Filters on Brownian Noise.- VIII. Detection of Signals.- IX. Multiple Sources of Noise.- X. Concluding Remarks.- XI. References.- 3. The Anatomical Organization of the Primate Auditory Pathways.- I. Introduction.- II. Morphological Aspects of the Auditory Pathway.- A. Cochlear Nuclei.- B. Superior Olivary Complex.- C. Ventral and Dorsal Nuclei of the Lateral Lemniscus.- D. Inferior Colliculus.- E. Cell Groups in Proximity to the Brachium of the Inferior Colliculus.- F. Medial Geniculate Body.- G. Auditory Cortex.- III. The Course and Distribution of Primary Auditory Fibers.- IV. Ascending Fiber Systems in the Central Nervous System.- A. Fibers Arising from the Cochlear Nuclei.- B. Efferent Connections of the Superior Olivary Complex.- C. Projections of the Nuclei of the Lateral Lemniscus.- D. Projections of the Inferior Colliculus.- E. Efferent Connections of the Parabrachial and Interstitial Nuclei of the Brachium of the Inferior Colliculus.- F. Geniculocortical Projections.- V. Other Connections.- VI. References.- 4. Vocal Communication in Primates.- I. Introduction.- II. The Auditory Signal.- A. Vocalization Repertoires.- B. Neural Correlates of Vocalizations.- C. Ontogeny of Vocalizations.- III. Perception of Vocalizations.- A. Auditory Sensitivity.- B. Responses of Single Auditory Neurons.- IV. Conclusions and Summary.- V. References.- 5. Structural and Functional Aspects of the Superior Colliculus in Primates.- I. Introduction.- II. Anatomical Studies.- A. Cytoarchitecture.- B. Fiber Connections.- III. Physiological Studies.- A. Visual Field Representation.- B. Unit Types in the Monkey Colliculus.- C. Functional Considerations.- IV. Behavioral Studies.- A. Ablation Studies.- B. Stimulation Studies.- V. Summary and Conclusion.- A. Anatomy.- B. Physiology.- C. Behavior.- VI. References.- 6. Parallel Pathways Connecting the Primate Superior Colliculus with the Posterior Vermis: An Experimental Study Using Autoradiographic and Horseradish Peroxidase Tracing Methods.- I. Introduction.- II. Materials and Methods.- III. Results.- A. The Tecto-Olivary Projection in the Rhesus Monkey.- B. The Cerebellar Target of Subnucleus b.- IV. Discussion.- V. References.- 7. The Organization of Visual Cortex in Primates.- I. Introduction.- II. The Visual Areas.- A. The Traditional View of Visual Cortex.- B. The Primary Visual Area.- C. The Secondary Visual Area.- D. Visual Areas beyond V II.- III. Connections.- A. Receiving and Projecting Neurons.- B. Ipsilateral Connections.- C. Callosal Connections.- IV. The Significance of Multiple Representations.- A. Evolution.- B. Development.- C. Functions.- V. References.- 8. The Relevance of Endocasts for Studying Primate Brain Evolution.- I. Introduction.- II. Possible Lines of Evidence for Brain Evolution.- III. Qualitative and Quantitative Descriptions.- IV. Toward Fuller Morphometric Analyses.- A. Study 1.- B. Study 2.- V. Addendum.- VI. References.