Asymmetric rotational (circling) behavior, a dopamine-related asymmetry: preliminary findings in unmedicated and never-medicated schizophrenic patients.

Circling behavior is one of the best understood behaviors in animals. It is, for the most part, dopaminergically mediated and related to asymmetry in dopaminergic activity between the left and right basal ganglia or left and right frontal cortex. As a rule, animals rotate toward the hemisphere with lower striatal dopaminergic activity. A direct technique to find human analogs of circling behavior was not available. We have developed an automated rotometer with which we can apply the circling rodent model to humans. Left-prone circling behavior (neglect of right-sided turning) was found in 10 unmedicated schizophrenic patients, whereas 85 normal controls demonstrated almost equal right and left turning. These preliminary results may suggest the presence of a dopaminergic asymmetry in some unmedicated schizophrenic patients; that is, right anterior subcortical or cortical structures of the brain may manifest a relative dopaminergic overactivity compared to left anterior structures in at least some unmedicated patients with schizophrenia.