286 



THE NERVOUS SYSTEM 



to the surface. By means of this cell and fiber lamination Brodmann (1909) 

 recognizes six layers in the cerebral cortex (Fig. 215). Other authors, notably 

 Campbell (1905) and Cajal (1906), number these layers somewhat differently. 

 Moreover, the arrangement varies in different parts of the cortex. In certain 



Via 



VIb 



> - >- 



4({\\$^ 



Fig. 215. Diagram of the structure of the cerebral cortex: 7, Molecular layer; II, layer of 

 small pyramidal cells; ///, layer of medium-sized and large pyramidal cells; IV, layer of small 

 stellate cells; V, deep layer of large pyramidal cells; VI, layer of polymorphic cells; ja 1 , band of 

 Bechterew; 4, outer band of Baillarger; 56, inner band of Baillarger. (Brodmann.) 



regions one or more of the strata may be reduced, enlarged or subdivided, but 

 the arrangement in most parts is substantially like that illustrated. The six 

 layers are as follows: 



1. The molecular layer (plexiform layer, lamina zonalis) is the most super- 

 ficial. It contains the superficial band of tangential myelinated fibers and many 



