The differential effect of right versus left hemispheric cerebral infarction on catecholamines and behavior in the rat.

Following right middle cerebral artery ligation in rats, there is a 2-3 week period of spontaneous hyperactivity. Concomitant with this hyperactivity catecholamine concentrations decrease in several areas of the brain including both cortical and subcortical regions. In marked contrast, there are no demonstrable effects of left hemispheric infarction on either spontaneous activity or brain catecholamine concentrations. This asymmetry of behavioral and biochemical response to cerebral infarction cannot be attributed to differences in the lesion size produced in either hemisphere. Feeding and drinking are not affected but the asymmetrical effect on activity can be demonstrated in either a home cage running wheel or an open field environment. It is uncertain whether these findings are the result of hemispheric asymmetries in either catecholaminergic or non-catecholaminergic neurons.