BRAIN LESIONS ASSOCIATED WITH PROLONGED UNCONSCIOUSNESS

Abstract

IN RECENT years a large amount of data has accumulated concerning the function of the central cephalic portion of the brain stem in animals, an area about which little had previously been known. This information stems from the work of Magoun and his associates, who pointed out that the cephalic tegmentum, subthalamus and hypothalamus, and the medial portion of the thalamus function as an "activating system," excitation of which resulted in desynchronization of electrocortical activity and behavioral arousal of a sleeping animal. Supporting the contention that this area had importance in the complex arousal mechanism were the observations of Lindsley and associates¹on the cat. They showed that electrolytic lesions strategically placed to destroy a portion of the region resulted in animals which were, among other things, chronically unresponsive to normally arousing stimuli and which continuously displayed a synchronous electroencephalographic tracing characteristic of stupor. Similar lesions in monkeys²