Decerebrate Animal

an animal whose cerebral cortex and the nuclei situated in front of the base of the subcortex have been surgically removed; most of the diencephalon, at the level of the thalamus, and most parts of the brain located behind it are not removed.

As the diencephalon contains higher subcortical centers of vegetative innervation, the decerebrate animal is capable of such basic vegetative functions as metabolism and thermoregulation. The more highly developed the animal, the more pronounced are the changes in its locomotor reactions. Decerebrate rabbits are practically indistinguishable from normal rabbits in their ability to perform locomotor acts. Decerebrate cats, however, remain in a sleeplike state in the postoperative period. When the skin is strongly stimulated, they respond with various locomotor reactions, such as running and jumping. Preening and scratching reflexes are retained by cats, but the animal salivates only when the food enters the oral cavity. Motor activity in decerebrate dogs decreases sharply—the animals are largely immobile and move only in response to strong stimuli. Decerebrate monkeys die shortly after the operation.

Reactions of decerebrate monkeys include trembling of the extremities, stereotypy, and inability to climb or to move the body normally. Decerebrate animals display typical body reactions usually associated with the sensation of pain. The intensity of their reactions is related to the absence of inhibitory influences of the cerebral cortex.