The most widely studied cortical network in primates is the distributed network subserving visuospatial attention. While the areas involved in this network are known, their neurochemical and connectional organization are not well understood. In order to characterize the functions of a distributed network, an understanding of the components of that network must be achieved. To that end, several distinct areas within the proposed network were examined chemoarchitecturally and connectionally. The areas investigated were the superior temporal polysensory (STP) cortex, the cingulate gyrus, and the parahippocampal gyrus (PHG). The STP cortex was examined in tangential sections immunostained for neurofilament protein, as well as cytochrome oxidase (CO) histochemistry. The posterior cingulate gyrus and PHG were examined using coronal sections immunostained for neurofilament protein, and thionin histochemistry. Within two subdivisions of the STP region, it was observed that a modular architecture was evident in both stains. In all cases, corticocortical tracing supported the parcellations observed with the histology. The cingulate and PHG were not observed to exhibit modular features with the neurofilament or Nissl staining. However, connectionally, there was evidence of modular organization within the posterior cingulate gyrus and to a lesser extent, the PHG. These results suggest that modular anatomy is not a feature restricted to low order sensory cortices, but is evident in higher order association cortex. Further studies are warranted to determine if neurochemical modules are evident in other higher order cortical areas in the primate brain
