Visual disturbances after cerebral lesions.

Abstract

(A review of literature: 271 titles.) Three chief lines of investigation may be distinguished. (1) Henschen's view that retinal points are projected upon the cortex in a circumscribed and point by point way, rather than diffuse as urged by von Monakow, tends to be strengthened by the bulk of clinical findings in connection with war cases. Localization in the area striata is favored by many. As to the cortical representation of color vision no definite results have been obtained. (2) Brain localization of higher optical processes, such as depth-perception, form-perception, etc., although much studied, is not in an advanced stage. It has been urged that the physiologist needs here to employ psychological methods in addition to his anatomical and pathological technique. (3) In the light of work on visual disturbances, cerebral localization in general is coming to be recognized as decidedly an open question. For instance, Goldstein makes the interesting suggestion that the two extreme views of von Monakow and Henschen may each be both right and wrong; as fibers from a specific retinal part may run not only to a localizable projection center but also diffuse more generally. Furthermore "we are likely to be fascinated by histological results when it is possible that electrochemical processes are the basis for function."

"Functions" of striate cortex and the problem of mass action.

“…Disturbances in "attention" have been emphasized by Poppelreuter (1917), Fuchs (1920), andGelb andGoldstein (1920) as a major symptom following gun-shot wounds in the occipital region. Kluver (1927) has reviewed the studies up to 1927 of visual functioning following trauma to the occipital cortex. It is possible to reinterpret some of the evidence in terms of "general dementia."…”

The nature and physiological basis of visual movement discrimination in animals.

“…The conclusions of clinical neurologists on retained capacity for movement discrimination in human subjects with injuries in the occipital lobes should be looked upon as tentative, since it appears that adequate material and methods have seldom been used. The difficulties inherent in the clinical material and technique have been covered in detail by Kliiver (30), Pieron (49), and others. Since the majority of cases on which observations of movement perception have been made have resulted from the chance wounds of war, clear-cut evidence as to extent and locus of pathological effects is often difficult to obtain.…”

Fragmentary eidetic imagery.

“…As regards the facts in the field of pathology, it is not possible to present even a condensed summary of the pathological literature in question. The reader is to be referred to the studies by Potzl (1, X5-17, 19), von Stauffenberg (23), Head (5), Poppelreuter (14), Pick (13), Hartmann (4), Gelb (2), Gelb and Goldstein (3), and to the widely scattered war literature on visual disturbances after cerebral lesions (8). To illustrate: Potzl's case, Obszut, for instance, a case with a relative paracentral scotoma, is shown a yellow cross on a white ground.…”