DYNAMIC ORGANIZATION OF MOTOR CONTROL WITHIN THE OLIVOCEREBELLAR SYSTEM

WHAT is the role of the cerebellum in motor coordination? Such coordin ation depends upon the integrity of the inferior olive, a major cerebe llar afferent, as its lesion produces ataxic and dysmetric movement ab normalities(1,2). Using multiple-microelectrode recordings, we report here that there are domains of Purkinje cell activity that are generat ed by olivary input during skilled tongue movements in rats, Such acti vity domains are highly rhythmic and time-locked to movement, Patterns of synchronous olivocerebellar activity are geometrically complex and can change during a sequence of movements. The results support the vi ew that the inferior olive organizes movement in time, by entraining m otor-neuronal firing through rhythmic activation of the cerebellum, an d in space, by synchronously activating cell ensembles that allow the use of individual muscles. Dynamic repatterning of olivocerebellar syn chrony may allow different combinations of muscles to be used for move ments intended to have varying spatial structures.