Doctoral Dissertation Improvement: Neural Substrates of Primate Communication: A Comparative Study of Facial and Hypoglossal Nuclei

Columbia University, New York NY

Investigators

Abstract

Primates use diverse sensory channels in their communication among social partners, ranging from the pungent "urine washing" of ring-tailed lemurs to the flamboyant "lip flip" gesture of gelada baboons to the complex rhythms of human speech. These signals are often highly nuanced and produced in a flexible, context-sensitive manner. Since the nervous system has a central role in the planning and execution of communicative behavior, one would expect significant species differences in the brain structures that subserve communication. To date, however, little is known about species differences in the brain's control of the orofacial system that is so vital to the production of facial expression and vocalization. This research project will contribute to our knowledge of the neural substrates underlying two important transformations in the evolution of primate communication: (1) the more dominant use of facial expressions among great apes and humans, and (2) the skilled use of the tongue and lips in the service of human spoken language. In a sample that includes New World monkeys, Old World monkeys, apes, and humans, brainstem regions that directly supply the muscles of facial expression and the tongue will be analyzed using techniques to reveal their chemical composition and cellular structure. The results of this study will help to clarify how neural organization determines species-specific communicative signals, including human speech, and will provide insights into the evolution of the primate brain