Symptoms of experimental catatonia in the audiogenic and electroshock reactions of rats.

Abstract

Experimenal catatonia was described originally by H. de Jong and H. Baruk (1) as occurring in different animals following the injection of certain doses of bulbocapnine. Later (2) it was found that this syndrome may be elicited by many other physical and chemical methods. Experimental catatonia is, therefore, a general reaction-form of the central nervous system. It may be subdivided into: (A) Hypokinetic and (B) Hyperkinetic forms.(A) HYPOKINETIC SYMPTOMS(1) Diminished motor initiative, i.e., the impulse to movements and acts is diminished. This may occur to such a degree that the animal remains motionless in a drooping position, always remaining in one spot for many hours.(2) Catalepsy. This is a variety of diminished motor initiative. The animal assumes positions passively introduced by the examiner. Catalepsy is not only limited to the extremities but is found in the whole body.(3) Negativism, a physiological phenomenon consisting of passive and active resistance to changes of positions already assumed.

Experimentally induced convulsive reactions of laboratory rats. I. A comparative study of the immediate reactions.

“…It will be recalled that the symptoms of experimental catatonia were induced by an average electrical tension of 65 volts passed for 0.2 second, while the average tension necessary to produce generalized convulsions was 85 volts maintained for the same time. Moreover, as the writer and De Jong (12) have already described, an animal which is only "shocked" by electricity without the production of any symptoms of the NF-3 and NF-4 pattern may nevertheless show incipient cataleptic posturing and resistance to passive movement.…”

“…Protocols detailing the appearance of the symptoms of experimental catatonia in the rat following various kinds of stimulation have been published by the writer and De Jong (12). Hyperkinesia in different forms, catalepsy, and negativism similar to the forms of experimental catatonia reported as occurring in various kinds of animals are also demonstrable in the rat.…”