Operant control of turning in circles: a new model of dopaminergic drug action.

Rats were trained, using water reinforcement, to exhibit high rates of rotation (circling) during one-hour daily test sessions. Preferred directions of learned rotation were the same as those determined previously in response to D-amphetamine. Changes in reinforcement parameters elicited predictable changes in rates of learned rotation. The effects of D-amphetamine, apomorphine, haloperidol and methohexital could be readily dissociated indicating that the operant rotation paradigm could likely become a useful behavioral assay of dopaminergic drug action.