Reorganization of bimanual motor responses on formation of a lateralized food-procuring skill in rats.

After 48-h food deprivation,Wistar rats were trained to reach a food sphere from a narrow horizontal feeder tube with one paw, with a free choice of limb. The animals used both limbs at the initial stages of training--seizing of food with one paw could alternate with seizing using the other paw, and both limbs could be involved alternately in movements preceding seizure of food. The dynamics of the reorganization of bimanual movement responses during the training of rats with different motor preferences (right-handed, left-handed) were studied. Bimanual movements in preliminary trials disappeared later than in movements ending with successful food extraction during the acquisition of both right-and left-sided skills. The disappearance of bimanual movements in preliminary trials was regarded as a measure of the maximum extent of lateralization of the skill and establishment of a new motor coordination. During training, left-handed rats reached the maximum level of lateralization of the skill earlier than right-handed rats.