Septal lesions enhance hyperactivity induced either by amphetamine or lesions of the nucleus accumbens septi.

Spontaneous locomotor activity was measured in 4 groups of rats subjected to either septal, accumbens, combined septal-accumbens or sham operations. Accumbens but not septal lesions increased activity above control levels and the combined septal-accumbens lesion markedly increased activity levels above that produced by the accumbens lesion. Thus, septal lesions appeared to exaggerate the activity changes produced by the accumbens lesions. Furthermore, both septal and combined septal-accumbens lesions enhanced the hyperactivity induced by 0.25, 0.5 and 1.0 mg/kg D-amphetamine-HCl but attenuated the hyperactivity induced by 0.25, 0.5 and 1.0 mg/kg scopolamine-HCl. Rats with accumbens lesions did not differ from controls in their response to amphetamine or scopolamine. Thus, septal lesions modified both lesion and drug-induced changes in locomotor activity.