Eric J. Lang, MD, PhD

The major focus of the laboratory is to investigate the neuronal basis of motor coordination. In particular, we are studying the relationship of the activity of two brain regions, the motor cortex and cerebellum, to movement.

The olivocerebellar system is one of the two major afferent systems to the cerebellum. This system is organized to generate patterns of rhythmic and synchronous activity, which evoke complex spike activity in cerebellar Purkinje cells. These periodic synchronous discharges are hypothesized to have a timing function that helps organize the activation of muscles to generate a movement. To observe the patterns of activity of the olivocerebellar system we employ a multiple electrode recording technique, which allows us to record simultaneously the complex spike activity from more than 100 Purkinje cells. We have been investigating the roles of excitatory and inhibitory inputs to the inferior olive in organizing these discharges. To do this we make pressure injections of GABAergic and glutamatergic antagonists into the inferior olive and investigate the resulting changes in the patterns of complex spike activity. We are also investigating how the motor cortex and olivocerebellar system interact to control the execution of a movement. The timing hypothesis suggests that the function of olivocerebellar activity may be to gate the ability of motor cortex activity to generate movements. That is, the olivocerebellar system may be helping determine the timing of descending motor commands from the cortex. To test this idea we are combining multiple electrode recording of complex spike activity with high speed videotaping of whisker movements evoked by motor cortex stimulation.