Chronic Experiment

in physiology, a prolonged study of the life processes of a healthy experimental animal or of one specially prepared for analysis by being subjected to appropriate treatment or surgery.

There are several methods of physiological surgery. Artificial access to internal organs may be effected, for example, by creating a fistula for sham feeding. Individual organs are extirpated in order to study subsequent disturbances in the organism, and innervation is altered by denervation and the suturing of nerves. Other methods of physiological surgery include altering the blood supply by means of anastomosis, and registering bioelectric activity by implanting electrodes in the brain or heart.

Chronic experiments are conducted after the complete restoration of the physiological functions that were altered by anesthesia or surgery. Chronic experiments have a number of advantages over acute experiments, in which the experiment is conducted during surgery itself or immediately afterward. A classical example of the chronic experiment is the experiment conducted after the creation of an isolated pouch (Pavlov’s pouch).