Instrumental conditioned responses in cats with bulbar pyramid and red nucleus lesions

Adult cats were trained to insert a forelimb into horizontally mounted transparent cylinders and then either depress a barrier or pull a sliding tray against resistance in order to receive food reward. Unilateral lesions of both bulbar pyramid and red nucleus resulted in severe neurological deficits. However, the instrumental tasks were soon accomplished at preoperative levels of rapidity and strength, although movements of the digits and wrist were reduced and adjustive movements occurred chiefly at more proximal joints. These results support our hypothesis that conditioned and unconditioned behaviors are mediated through different mechanisms.