A comparison of EEG modifications induced by coagulation of subthalamus, preoptic region and mesencephalic reticular formation

Abstract

Lesions were made in the subthalamus and reticular formation of the mesencephalon in ninety-three cats, both acute and chronic preparations. Four types of EEG change were observed after subthalamic lesions, the most frequent of which was the production of spindles. The path of approach resulted in some variation of results. Unilateral subthalamic lesions produced ipsilateral EEG changes. Sensory stimulation reestablished the pre-lesion pattern. Large unilateral lesions of the mesencephalic reticular formation which were made with a horizontal approach and which did not cross the midline did not produce cortical spindles. Lesions in the anterior pole of the thalamus blocked spindles produced by subthalamic lesions as well as those produced by Nembutal.