Hierarchical structure of visual functions

A study of visual functions by electroconvulsive shock method

Abstract

The purpose of this study was to examine the difference amoung recovery time of the various visual functions following electro-convulsive shock and to ascertain whether the visual functions form a hierarchical structure or not.
Procedure
Electroshock : A convulsive seizure was induced in the patient by applying electricity through electrodes of 60 mm in diameter placed on his auricles.
Administration of tests : Tests were administered before and after the shock.
Subjects : The subjects studied were mental patients, who were not greatly disturbed and were capable of cooperating in test situation. The number of subjects used amount to 64.
Kinds of tests : a. The perception of the absolute direction based on the subject himself. b. The discrimination of colors. c. The perception of forms based on supplementation. d. The renaming of colors. e. The simultaneous size-comparison of objects. f. The simultaneous comparison of square dimensions. g. The selection of an identical size. h. The perception of directions on a plane. i. The size comparison of figures based on memory. j. The evaluation of line-length by memory. k. F-G phenomenon. l. The solid perception of figures drawn on a plane. m. Rorschach Test.
Results and Discussion
1. The perception of absolute direction based on the subject himself recovered first, followed by the simultaneous size-comparison of objects and the square dimensions. Next, the perception of directions on a plane recovered. In due time, the selsction of the identical size recovered.
2. In color perception, the discrimination of colors recovered first. Next, the re_??_aming of colos such as “red” “black” and “white” fixated since early childhood recovered. The perception of forms based on supplementation recovered the last of all.
3. The recovery time of size comparison of figures based on memory, the evaluation of line-length by memory and the solid perception of figures drawn on a plane was more prolonged, as compared with the recovery time of the above mentioned visual functions.
4. In F-G phenomenon, Black space was perceived as a “figure” and as time elapsed, white space was perceived as a “figure”.
5. A phase of Rorschach records conformed with the above mentioned recovery order : that is, the simple color-naming response, which is a primitive response patern, appeared in the earlist records, the movement response which is of a higher order, appeared always the last in the records.
6. The various functions of visual perception did not recover at the same time, viz., the recovery time varied according to the differences of visual functioss and levels of function involved in the same function. The course of recovery is shown in Fig. 7. The abscissa indicates the time-passage after the shock period, and the ordinate, the various visual functions. The recovery process displays notable characteristics, namely, it indicates the recovery starting from the lower functions and going on to the higher functions. Consequently, we suppose that the various visual functions form a hierarchical structure, which, it is assumed, depends on the stratum of the cerebral cortex.
It seems that electro-shock disturbs the surface of the upper parts of the cerebral cortex most markedly, while its effect apparently weakens reaching to ward the bottom stratum. Therefore, in the recovery time the bottom stratum of the cortex recovers more quickly than do the upper ones.
The difference of recovery time of the various visual functions substantiates a hierarchical hypothesis of the visual functions.