Sponsor: FES Center Cleveland
Wolstein Research Building
Room1413
case.edu/livestream/fes
Reza Shadmehr, PhD, MS
Professor of Biomedical Engineering and Neuroscience
Johns Hopkins University School of Medicine
Neural computations in the cerebellum during control of a movement
Damage to the cerebellum typically causes dysmetria, affecting endpoint accuracy. What is the cerebellum computing that is so
important for stopping a movement? In the marmoset, we have been studying saccadic eye movements, using silicon probes to
quantify both the information that the cerebellar cortex receives via mossy fibers and climbing fibers, and the output it produces
via Purkinje cells (P-cells). Our results suggest that the input encodes two different kinds of information: the goal of the movement
in sensory coordinates, and the ongoing commands in motor coordinates. The output, as computed by populations of P-cells,
produces a burst that rises analogous to predicting the real-time displacement of the eyes, and then suddenly and synchronously
is inhibited when the eyes need to decelerate and stop. Thus, we speculate that the cerebellar cortex is computing in real-time
the sensory consequences of the motor commands until it reaches a bound, as set by the desired goal of the movement, at which
point the P-cells synchronously disinhibit the nucleus, thus stopping the movement.