Conditioning of fine motor control in neonatally undernourished rats

The literature indicates that the effects of developmental undernutrition on the rat nervous system are disproportionally found in the cerebellum, an organ involved in motor coordination and control. In this experiment, rats who had been developmentally undernourished did not show increased variability of forces placed on a bar by the paw in an operant learning paradigm, indicating normal motor control function. However, deficits were obtained when reinforcement was made contingent on bar press force regulation. Experimental rats shifted bar pressing forces to meet criterion more slowly than controls and received fewer reinforcements over training trials. The data are discussed in terms of recent suggestions that the cerebellum is directly involved in motor learning processes.