Conditioned rotational behavior in rats with unilateral 6-hydroxydopamine lesions of the substantia nigra.

Rats with unilateral 6-hydroxydopamine lesions of the substantia nigra were given drug treatments which induced rotational behavior either ipsilateral (2.0 mg/kg D-amphetamine) or contralateral (0.5 mg/kg apomorphine) in a classical conditioning paradigm. Four days after four drug-environment pairings the rats rotated ipsilateral in the amphetamine-associated environment and contralateral in the apomorphine-associated environment. 6-OHDA-lesioned rats which received only drug or environment exposure exhibited a slight tendency to rotate ipsilateral in each environment. This conditioning of drug-induced rotational behavior may offer a useful model for the study of brain mechanisms in classical conditioning.