BEAM SENSORIMOTOR LEARNING AND HABITUATION TO MOTOR-ACTIVITY IN LURCHER MUTANT MICE

Lurcher mutant mice lose cerebellar granule cells and Purkinje cells. The mutants were compared to normal mice in a beam-walking task. Norma l mice were placed on a slippery bridge while lurchers, because of the ir severe ataxia, were placed on a bridge with the same diameter, but enveloped with surgical tape to improve traction. The performance of b oth groups improved with repeated trials. In an activity box, lurcher mutants were as active as normal mice, showed normal intrasession habi tuation, and emerged from a toy object as easily as normal mice. These results indicate that the cerebellar damage in lurchers does not prev ent the acquisition of a motor skill task requiring balance in an immo bile apparatus. Ataxia was not accompanied by hypoactivity, inhibition or disturbances in intrasession habituation.