The recovery of locomotion following partial extirpation of the motor cortex and transplantation of cortical tissue in the white rat.

The changes in the parameters of locomotion in three groups of white rats at ages from 5 to 16 weeks were investigated in this study: 1) following unilateral extirpation of an area of cerebral cortex in the zone of the motor representation of the hind limb at the age of 5 weeks; 2) following homotypical transplantation of cortical tissue from newborn rats to the zone of decortication at the same age; 3) intact animals of the same litters (control). An age-related increase in the step length took place in the rats of all groups. By contrast with the intact rats, in which the increase in the values of the step length and width took place smoothly over the course of the entire period, a lag in the locomotion parameters investigated was observed in the operated animals. After two to five weeks the features of recovery were already observed in the grafted rats, while a tendency toward an alteration in the character of the gait was detected after 9 to 11 weeks: their step length exceeded that of both the operated and intact rats. Histological control confirmed the taking of all grafts without signs of rejection or necrotic changes. The possible mechanisms of participation of endogenous and exogenous factors in the elimination of the hemiparetic sequelae are discussed.