Journal ot VeStibUlar Kesean.:u, I, ki..), PI'" ./,. Copyright © 1997 Elsevier Science Inc. Printed in the USA. All rights reserved 0957-4271/97 $17.00 + .00 PH S09S7-4271(96)00183-8 Original Contribution HOW TO CONSTRUCT AND MOVE A CAT'S NECK W. Graf,* E. Keshner,t F. J. R. Richmond,+ Y. Shinoda,§ K. Statler,11 and Y. *CNRS-College de France, 75231 Paris Cedex OS, France, tRehabilitation Institute of Chicago, Chicago, Illinois 60611, USA :j::Department of Physiology, Queen's University, Kingston, Ontario K7L 3N6, Canada, §Department of Physiology, School of Medicine, Tokyo Medical and Dental University, Yushima, Tokyo 113, Japan, IIDepartment of Physiology and Biophysics, Northwestern University, Chicago, Illinois 60611, USA, of Physiology, Tokyo Medical College, Shinjuku, Tokyo 160, Japan Reprint address: Werner M. Graf, CNRS-LPPA, College de France, 11 place Marcelin Berthelot, F-75231, Paris Cedex 05, France. Tel:+33-1-44-27-16-30; Fax: +33-1-44-27-13-82; E-mail: wg@ccr.jussieu.fr Abstract - Extensive information has been ac- ulated over the past several years about the sensory-motor system, in particular relating to cats. Using still x-ray and cinera- analysis, the skeletal geometry of md.-neCK posture in three dimensions--when an is resting, actively orienting, or locomot- described. From these descriptions, cervi:.. vertebral, and craniocervical joint biome- for all three rotational dimensions are lantified. These behavioral data on muscle and movements have been incorporated in a biomechanical, functional anatomical model of the Ilead-neck movement system. Individual as well groups of neck muscles have been measured in and their kinematics determined. The role several reflex and voluntary behavioral contexts, including muscle co-contractions. Having lished how each movement is accomplished, the neuronal sensory-motor reflex basis of head-neck system stabilization in space is addressed. The ves- tibular system is largely responsible for acquisi- tion and maintenance of upright posture. The bi- lateral semicircular canais (horizontai, anterior, posterior) and otoliths utriculus) feed information differentially to specific neck mus- cles: these connections are reviewed with regard to the origin of the reflex arc from each receptor to its destination of specific muscles. Behavioral data from normal animals, and from animals whose vestibular receptor systems are selectively lesioned, will be reviewed to complement the func- tional interpretation of the sensory-motor trans- formations. Finally, the requirements for space- time coordinated cat head-neck movements will be synthesized, based on biomechanics, muscle ki- nematics, canal/otolith connectivity, and selective lesion experiments. © 1997 Elsevier Science Inc. D Keywords - head-neck; stabilization; cat; sensory-motor; posture. Introduction The head-neck movement system provides an excellent model for studying sensory-motor transformations, because most of the contribut- ing sensory and motor systems are well- researched and described. This review provides a complete description of three areas necessary to describe postural and reflex control of the head-neck movement system: head-neck joint biomechanics, cervical muscle geometry/kine- matics, and the vestibular sensory input to neck muscles subserving vestibulocolIi::.' reJ1exes. SkeJ- etal geometry during movement 11as been mea- sured by x-ray and cineradiography (1-4), and neck muscle kinematics have been determined for severa] reflex and voluntary behavioral con- texts (1,2,5-9). These data have been incorpo- rated in the most thorough head-neck move- ment model to date. A detailed description of the vestibular sen- sory input to neck muscles and behavioral data 219