Effect of Metrazol on Recent Learning

Abstract

One of the theories attempting to explain the mechanism of metrazol treatment in the psychoses is that a noxious or destructive effect is exerted on the central nervous system so that the mental symptoms, affecting neural processes of the highest order (largely cortical), and also of most recent origin, are the most vulnerable and hence the first to disappear. In order to further test the validity of this concept we attempted to establish a neural pattern of recent origin and see if it could be abolished by the administration of metrazol.

The demonstration required the establishment of new learnings of a fairly high order which were amenable to objective experimental control, observation and measurement. The code transcription procedure was chosen as a simple technic which would satisfy these criteria.

The following routine was observed for the experiments: After preliminary explanations and demonstration, the patient was asked to transcribe from memory the nonsense syllable code in the appropriate blank spaces as rapidly as possible. He worked 4 minutes; his score was the number of items transcribed. After 2 minutes' rest he was given 6 minutes of practice at transcription. Then followed another 2-minute rest interval and a 4-minute retest. The number of items transcribed in this latter period constitute the “Retest 1” score. During the week following Retest 1, two or 3 metrazol injections were administered. At the end of the week another 4-minute retest was given; the number of items transcribed constitute the results of Retest 2. By comparing the scores made on Retest 1 and 2, any change in the patient's performance could be determined.

An alternate and comparable form of the code transcription test was used on the same patients (Control I).