Abstract: 168 Wistar rat pups were assigned to 11 age groups from 0, 2, 4, 6……to 20 days. All subjects were tested for the rotational behavior inducedby amphetamine (50mg/kg i. p.). The purpose is to study ontogeny offunctional asymmetry of the two cerebral hemispheres in rats. The test showed that the rotation with low level in O-day-1 old (post-natal 0-12 hrs) pups can be induced by amphetamime, and the level ofrotation was enhanced with each passing day. The results indicate that inrats the two cerebral hemispheres were characterized by asymmetry atbirth.

Key words: NULL