" Field 41, the most distinctive and readily defined cytoarchitectonic field of the tem- poral region, is positioned as by Krieg. " " The cortex of field 41 is intermediate in width between that of parietal and occipi- tal fields. The cortical widths in fields 22 and 36, by contrast, are relatively nar- row. " " In areas 41 and 22 cells are relatively widely spaced. A separate layer I1 is not demar- cated from 111. The granule cells of layer IV are larger and more widely spaced than in the parietal and occipital regions. The pyramidal cells of layer V, on the other hand, are relatively small in comparison, and there is no hypocellular zone in sub- lamina Va. There is thus little cytologic differentiation of layers I11 through Vb, a distinctive feature of both fields 41 and 22. It is an equally distinctive feature of both these temporal fields that a hypocellular zone is well developed in sublamina Vc. Layer VI is narrow and dominated by globu- lar cells. The sublamina VIb of fusiform, tangentially aligned cells is very narrow in fields 22 and 41 in contrast to its sub- stantial width in parietal and occipital fields. As in occipital cortex, but in con- trast to the pattern in parietal cortex, radial fibers traverse areas 22 and 41 singly rather than in fascicles. The density of radials and of the tangential strata in layers 111, IV, V and VI is intermediate between that in the parietal and occipital areas. Field 22 is narrower than 41. Architectonically it differs from field 41 in that layer IV is narrower and less cellular, and the cells of layer V are even smaller than in field 41 . Fiber density is greater in field 41 than in field 22, which forms a narrow zone of reduced fiber density between field 41 and the adjacent parietal fields. By con trast the fiber density of field 22 is equal to that of adjacent field 18a at more caudal levels. "
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