1932] Poliak: Afferent Fiber Systems, Primate Cerebral Cortex 265 







Fig. 60, Experiment II. This figiu-e shows a portion of figures 9 and 48 cor- 

 responding wdth the bottom of the central sulcus, under higher magnification 

 (about 60 x). It shows the minute relations of the afferent thalamic fibers to 

 that portion of the somatic sensory cortex which represents its "nuclear or 

 focal zone." (Compare also with fig. 2 and 7.) This zone corresponds approxi- 

 mately with Brodmann's field 3 being the most anterior portion of the post- 

 central granular cortex buried entirely in the central sulcus. This portion of 

 the extensive pre-postcentral somato-sensory region is most richly supplied by 

 the afferent fibers originating in the thalamus. The number of exogenous 

 fibers in the infragranular cortical strata is here considerably above that either 

 in the agranular precentral "motor" cortex or field 4 of Brodmann (figs. 61, 62), 

 or in the remaining postcentral granular cortex or fields 1 and 2 of Brodmann 

 (figs. 58, 59). Tlie stripes of Baillarger, the semicircular finely dotted zone in 

 the upper portion of the figure, is filled with the fine black detritus of the 

 disintegrated myelin. A few fine degenerated fibers, however, reach the supra- 

 granular layers as shown also in figure 9. 



