[Changes in functional motor asymmetry during aging and after irradiation]

We studied the changes in functional motor asymmetry in female CBA mice during the course of natural aging and after irradiation of the head with 10 Gy. The functional motor asymmetry was assessed by the behavior 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 calculated for the population. The asymmetry-age relationship in irradiated and intact mice has a similar shape with a distinct peak at the age of 13-17 months. The control population features a predominance of right turns, while left turns are specific for the irradiated one. This behavioral inversion is due to radiation-induced brain disturbance: the dominant left hemisphere proved to be more sensitive. Possible different rates of hemisphere aging is discussed.