CHANGES IN FUNCTIONAL MOTOR ASYMMETRY IND UCED BY AGING AND IRRADIATION

We studied the changes in functional motor asymmetry in female CBA mic e during the course of natural aging and after irradiation of the head with 10 Gy. The functional motor asymmetry was assessed by the behavi or of the animal in a T-shaped maze. The proportion of right turns in ten attempts was recorded for each mouse and the asymmetry index was c alculated for the population. The asymmetry-age relationship in irradi ated and intact mice has a similar shape with a distinct peak at the a ge of 13-17 months. The control population features a predominance of right turns, while left turns are specific for the irradiated one. Thi s behavioral inversion is due to radiation-induced brain disturbance: the dominant left hemisphere proved to be more sensitive. Possible dif ferent rates of hemisphere aging is discussed.