[The ontogenetic dynamics of hemispheric asymmetry in controlling the behavior of rats of either sex].

Dynamics of behavioural control in the open field was studied in Wistar rats of different sexes in the course of postnatal ontogenesis. Ethological analysis of behaviour in the open field was used combined with the temporary inactivation of the hemisphere cortex by means of spreading depression. Two main types of the ontogenetic dynamics of asymmetry were established. The first one was characterized by the right-left-right pattern of asymmetry, the second one by the left-right-left pattern. The first type of asymmetry dynamics prevailed in females, the second type was dominant in males. During different periods of ontogenesis, asymmetry of hemisphere control over the same behavioural acts in rats of opposite sexes could be both counterphasic and synphasic. The first type of the asymmetry dynamics is supposed to be connected with hemisphere control of avoidance behaviour, whereas the second one seems to be involved in exploratory behaviour. In males the open field behaviour is more determined by the exploration component, whereas in females avoidance component prevails.