1932] Poliak: Afferent Fiber Systems, Primate Cerebral Cortex 3 



during" the past decades, the mechanisms of mental processes, the 

 cortical organs involved in these, and the means and modes of their 

 integration remain for the most part imperfectly understood. As will 

 be shown in the course of this treatise, a close acquaintance with the 

 subject soon makes it evident that not only in many minor problems 

 is there uncertainty, but that some major conceptions regarded at 

 present as fairly well established can scarcely survive an impartial 

 critical examination, while others need the corroboration of new 

 investigations. No wonder that the old problem of the localization of 

 cerebral functions is again raised. Though the doctrine that the cir- 

 cumscribed areas of the cortex have a distinctive function is accepted 

 by the majority of neurologists in some form or other, we observe a 

 tendency in modern times again to question the strictly localistic view- 

 point. The alternative conception, especially noticeable in certain cur- 

 rents of modern experimental psychology and in many physiological 

 and clinical works (compare Head, Berze, Goldstein, Monakow- 

 Mourgue, Kohler, Sehroder, Hines, Collier, Brugia, Niessl von Mayen- 

 dorf, et at.), may be termed "equipotentialistic" and approaches more 

 or less the ancient doctrine of Cams, Longet, Vulpian, Flourens, Goltz, 

 and others of the functional omnivalence, or equivalence, of the entire 

 cerebral cortex. Though there may perhaps be certain localities of 

 the cerebral cortex connected with simple receptive processes, modern 

 omnipotentialists assert that all major activities of the brain, and per- 

 haps even the functions which appear as "partial," are products of 

 the working of many areas and regions of the cortex or even of the 

 entire brain. (Compare Chapter XVIII and the footnote to p. 217.) 

 In searching for the cause of these differences of opinion, one per- 

 ceives that it Ues mainly in the relative value placed upon the argu- 

 ments on which the modern localistic doctrine is built up. Many of 

 these arguments are not sufficiently convincing to eliminate the influ- 

 ence of personal opinion. This in turn is due largely to the absence 

 of reliable anatomical data, as justly pointed out by Vogt (1919, 

 pp. 285, 444), and as will be shown later in this treatise. This leads 

 some to deny any intimate relationship between definite functions and 

 cortical localities and to explain all higher cerebral processes by 

 "dynamic" factors; it, also, accounts for the comparatively scant 

 attention bestowed by psychologists and psychiatrists upon cerebral 

 anatomy and physiology, though it must be admitted that this is partly 

 due to the failure of modern brain anatomy to cooperate with these 

 sciences in intensive attacks upon major problems. 



