RECORDING EYE-MOVEMENTS IN MICE - A NEW APPROACH TO INVESTIGATE THE MOLECULAR-BASIS OF CEREBELLAR CONTROL OF MOTOR LEARNING AND MOTOR TIMING

The vestibulocerebellum is involved in the control of compensatory eye movements, To investigate its role in learning and timing of motor be havior, we investigated compensatory eye movements in mice with the us e of search coils, Wild-type mice showed the ability to increase the g ain of their vestibule-ocular reflex by visuovestibular training, This adaptation did not occur in lurcher mice, a natural mouse mutant that completely lacks Purkinje cells, During the optokinetic reflex the ph ase of the eye movements of lurcher mice in reference to the stimulus lagged behind that of wildtype littermates, whereas during the vestibu le-ocular reflex it led that of the wild-type mice, During combined op tokinetic and vestibular stimulation, the phase of the lurcher mice la gged behind that of the wild-type mice at the low stimulus frequencies , whereas it led the phase of the wild-type mice at the high frequenci es, In addition, the optokinetic response of the lurcher mice showed a significantly longer latency during constant-velocity step stimulatio n than that of the wild-type mice. We conclude that Purkinje cells are necessary for both learning and timing of compensatory eye movements in mice, The present description of gain adaptation and phase dynamics provides the basis for studies in which the molecular mechanisms of c erebellar control of compensatory eye movements are investigated with the use of genetically manipulated mice.