RESPONSES TO ELECTRICAL STIMULATION OF CAUDATE NUCLEUS IN CATS IN CHRONIC EXPERIMENTS

Abstract

Electrodes (106) were placed in and around the caudate nucleus. Stimulation by means of 60 cycle sine wave current was carried out in the unanesthetized state. Location of the electrode positions was controlled histologically. Contralateral trunk turning, was common to all points within the caudate nucleus (66 points). Contralateral fore-leg lifting occurred from about three-fourths of the points. They were most numerous in the middle and posterior thirds of the head of the caudate nucleus. Hind leg lifting, also contralateral, was elicited from one-third of the points, the majority of which was within the posterior 3rd of the nucleus. In chronic experiments after time for degeneration of the descending fibers in the internal capsule from the frontal part of the brain including the fontal, sigmoid, coronal and anterior ectosylvian gyri, neck and trunk movement and fore leg movements persisted. No inhibitory activity could be demonstrated with stimulation of the caudate nucleus. Cessation of walking, like that elicitable from the cingulate cortex, occurred upon stimulation of the lower portion of the internal capsule near the caudate nucleus. A delayed inactivation of the cats occurred with repeated stimulation (4 seconds, 1 minute intervals) of the caudate nucleus. Responses from 40 points in structures surrounding the caudate nucleus constitute control data.