1. A high degree of stability of the position of the cortical areas of the motor representation of the fore and hind limbs has been shown in intact rats; within those limits individual variability of the zones of the motor representation of individual joints was observed within those limits. 2. Following the partial left-sided decortication of the adult animal, the restructuring of the somatotopic organization of the motor cortex of the unoperated hemisphere is observed only in the late postoperative periods (about 0.5 year). A widening of the total boundaries of the area of effective intracortical microstimulation in the caudal direction, and a decrease in the relative proportion of the motor responses of the distal muscles of the extremities as compared with the proximal muscles and the muscles of the trunk, were observed. 3. An increase in the expressivity of the motor responses of the axial musculature (thoracic, pelvic, lumbar divisions), more than two-thirds of which are represented by bi- and ipsilateral reactions by the end of one after the operation, is observed at prolonged periods postoperatively.