1932] Poliak: Afferent Fiber Systems, Primate Cerebral Cortex 195 



tion, and transmission of individual li^ht stimuli to the cortex of the 

 great hemispheres. These studies do not allow any other conception of 

 the fundamental work of the visual system than a faithful transmis- 

 sion of retinal "figures" upon the visual cortex. Yet some modern 

 investigations, notably those of the "Gestalt" psychologists (Poppel- 

 reuter, Kofflca, Kohler, et al.), demand a supplementing of the above 

 conception. As these studies claim, the impression and the image of 

 an external object is not a mere aggregation or a mosaic of small, 

 independent, individual stimuli coming to a fusion somewhere in the 

 central organ, but is a "total" psycho-biological phenomenon, a 

 "figure" ("Gestalt" or "Form" of the German authors) with a 

 meaning of its own. Each figure or configuration is at once in its 

 totality recognized as such and not by a gradual additive process of a 

 number of small individual stimulations. As a particular example a 

 triangle, or a quadrangle, or a circle is under certain circumstances 

 immediately and completely recognized ; or a complete circle may be 

 seen though a part of the circle (object) may not exist (the missing 

 part corresponding to the blind halves of the field of vision, as for 

 example in cases of complete homonymous hemianopsia) . By some yet 

 unknown "totalizing" and "simplifying" central process, the imme- 

 diate reception of "whole" forms or "figures," and the comparison 

 of various sizes and shapes would, due to some innate tendency of the 

 central organ to create simple, finished, or "closed," forms or figures, 

 be achieved regardless of the previous experiences. Without further 

 questioning the correctness of all points of the "configuration doc- 

 trine" ("Gestalt "-psychology), especially its denying of the "isola- 

 tion" of reception and conduction of individual stimuli (compare the 

 above lines), it could be asked in what way and by what nervous 

 mechanisms that "totalization," "completion" and "rectification," 

 and in the cases of optic illusions, the distortion of the figures is 

 accomplished. For any casual explanation of these phenomena, the 

 structures, or at least the spot or level in the visual system, must be 

 determined. It seems on the one hand that for the genesis of the 

 above mentioned phenomena, the strictly "spatial" organization of 

 the visual system is an indispensable requirement, since no "figures" 

 whatever can be imagined in a system organized homogeneously and 

 working as a " whole. ' ' But this alone is evidently not sufficient. Side 

 by side with the principle of "isolation" and "localization" another 

 principle must be postulated, a mechanism by which the acts of 

 ' ' totalization ' ' and ' ' completion ' ' are performed. Whenever a ' ' closed ' ' 

 or a definite form is i^erceived, or whenever a "gap" in perception 



