Aiming to extend previous findings, male Wistar rats were treated per os for 13 weeks with manganese chloride in two doses: 300 mg/kg body weight (group I) and 20 mg/kg b.w. (II), the former was associated (III) with a microdose (1 ppm) of natrium selenite. The findings show an impairment of active avoidance learning in group III, a decrease of swimming performance and histological lesions in several brain areas (both especially in group III), changes of the aggressive behavior and decreases in the brain tissue of superoxide dismutase activity (I & II) and of lipid peroxidation (in all groups).