In higher primates, the motor-related areas of the neocortex are highly differentiated into several subareas based on both functional and cytoarchitectural aspects. To assess the molecular basis of this areal specialization, we investigated the gene expression profiles of the primary motor area (M1), premotor area (dorsal and ventral, PMd and PMv, respectively), and prefrontal area (A46) in rhesus monkeys using DNA microarray. We discovered that 476 genes were differentially expressed among these 4 areas. More than half of these genes were most abundantly expressed in M1, and most genes were complementarily expressed between M1 and A46. The expression profiles of PMd and PMv were quite similar to each other and different from those of M1 and A46. The data will provide a fundamental basis for the further analysis of the structure-function relationship of the primate brain. (c) 2007 Elsevier Inc. All rights reserved.