Rotation in the 6-OHDA-Lesioned Rat

Rotation is one of the most widely used tests in behavioural neuroscience. It is designed to detect motor turning and side biases in animals with lesions of basal ganglia circuits of the brain, and most notably ­following unilateral dopamine-depleting 6-OHDA lesions of the nigrostriatal bundle. When activated by stimulant or dopamine agonist drugs, rats and mice turn vigorously in circles for the duration of drug activity, yielding a reliable and easily quantifiable measure of the extent of the lesion and mechanism of drug action on the unbalanced dopamine system in the host brain. The design of automated rotometer test apparatus is discussed in detail, with advice for selecting the features most appropriate for different experimental applications. The selection of drugs, doses, time frames and testing protocols are then described, again in terms of the general principles that are readily adapted to particular experimental applications. Finally, a series of notes consider frequently asked questions related to practical issues involving drug selection, drug sensitisation, multiple testing and test spacing, and theoretical issues related to why and how does an animal rotate, and conditioning effects on the rotation response.