Analysis of Forced Circling Induced by DFP and Ablation of Cerebral Structures

Abstract

The effects of unilateral ablation of specific prosencephalic structures in rabbits induced to circle by the administration of DFP into the right common carotid artery were studied. In most cases, ablation of the cortex did not stop the circus movements, whereas excision of the right caudate nucleus in animals circling contralaterally usually stopped this behavior. Ipsiversive turning, however, was not usually affected even with bilateral removal of the telencephalon, a finding which indicates that mesodiencephalic structures may be involved in ipsiversive responses produced by intracarotid injections of DFP. This result, together with cholinesterase activity measurements, support the conclusion that in the rodent the nucleus caudatus is principally involved in contraversive responses and mesodiencephalic structures may be important to ipsiversive turning following an injection of DFP into the right carotid artery.