所長招聘セミナー

日 時 2013年07月02日 11:00~12:00
場 所 生理研 1階  セミナー室
演 者 Prof. Callum F. Ross(Deapt. of Organismal Biology & Anatomy Univ. of Chicago)
演 題 The evolution of rhythmicity in vertebrate feeding and locomotion
要 旨

Abstract: Mammalian feeding provides a rich source of material for evolutionary neuromechanics: the use of comparative behavioral, physiological, and morphological data to test hypotheses about the origin and evolution of sensorimotor systems. Mammals suckle their young, with a weaning period of transition from suckling to chewing. Mammals also employ a unique form of chewing: mastication, characterized primitively by transverse movements of precisely occluding teeth. Mastication evolved in the morphological context of reduced mandibular postdentary bones, reduction in tooth replacement to a condition of diphyodonty, a shift from ankylosis of teeth in the dentary to anchoring the teeth to the mandible via a richly innervated periodontal ligament, and the development of gamma-motoneurons for control of muscle spindles. Biomechanical modeling suggests that early mammals could also modulate muscle activities to control loads at the jaw joint and teeth. Mammalian mastication is also more rhythmic than the chewing of lizards and fish. High rhythmicity is hypothesized to facilitate motor control, especially tongue-jaw coordination.Our recent discovery that mammals and birds locomote with higher rhythmicity than other terrestrial vertebrates suggests that high rhythmicity characterizes multiple musculoskeletal systems, and might improve energetic efficiency. Our recent work on the role of cortex in control of primate feeding suggests an important role for cortex in control of mammal feeding, including possibly rhythmicity. The sensorimotor cortex precisely encodes 3D jaw and tongue movements and coordination, and manifests changes in dynamical states with changes in cycle type. The large number of unique sensorimotor components in the mammalian feeding system and the increases in brain size characteristic of mammals suggests that studies of the role of cortex, cerebellum and basal ganglia in control of mammal feeding promises important new insights into the origin and evolution of complex sensorimotor systems.

連絡先 畑中伸彦(生体システム研究部門 内線7772)hatanaka@nips.ac.jp