MIND, BRAIN AND BIOCHEMISTRY 391 



but also to the nerve cells which happen to be arranged in 

 certain groups or patterns. Anatomically these patterns are 

 regions such as the cerebral cortices, the cerebellum and a 

 number of sub-cortical structures. Refined observation reveals 

 that the neurons are often grouped in smaller functional areas, 

 or units called " nuclei," Chemical studies of the brain reveal 

 regional differences both qualitative and quantitative that may 

 be reflective of functional heterogeneity. 



Even if direct experimental evidence were not available, one 

 could conclude on other grounds that the brain displays some 

 localization of function. The functions of the brain are nu- 

 merous, as evidenced by the sensory functions of the mind; 

 and a multiplicity of simultaneous functions requires a mul- 

 tiplicity of parts. Increasing complexity of activity requires a 

 corresponding increase of material parts, though not necessarily 

 in a one-to-one relationship of part to function. Now, since 

 there is a multiplicity of organic parts, these parts must occupy 

 different places in the brain. In other words, there must be a 

 spatial organization of parts, not haphazardly disposed, but 

 according to the operational dependence obtaining among them. 

 It follows, then that a nmltiplicity of functions, requiring a 

 plurality of parts, will require a localization of these functions. 

 By this is meant that particular functions will be associated 

 with certain anatomical areas and perhaps even with bio- 

 chemical topography. Nevertheless, there is at times consider- 

 able overlapping. 



Over the years, our knowledge of localization of functions 

 has become more precise.'' (Yet this is not to deny that in 

 certain activities the whole brain apparently is involved.) The 

 mass of material which has accumulated has been authorita- 

 tively and comprehensively reviewed in three volumes of a 

 recent publication.^ The various projection areas for motor or 



* R. W. Gerard, " Neurophysiology, Brain and Behavior," in S. Arieti, op. cit., 

 pp. 1620-38. 



^ J. Field, Handbook of Physiology, Sect. I, Neurophysiology (Washington: Am. 

 Physiological Soc, 1959-60) . 



