Publisher Summary This chapter discusses the functional correlations of cortical areas. Neuronal circuits of the cortex are arranged in vertical columns, most evident in sensory areas. The neurons in each column have a common receptive field; they respond to and process the same stimuli. A column has its own pattern of afferent, efferent, and internuncial fibers. The human cortex excels in its multitudinous stellate neurons that form complex vertical inter laminar circuits and also link adjacent columns. Columnar organization is demonstrable in the primary visual cortex where input from right and left eyes alternates in ocular dominance columns. Cerebral white matter is a compact mass of vast numbers of association, commissural and projection fibers, and associated neuroglia. The cerebral cortex is not divided into exclusively somatomotor and somatosensory regions. The pre- and postcentral areas are both sensorimotor, the former predominantly motor and the latter sensory. There are supplementary somatomotor and somatosensory areas. The cortex can be regarded as consisting of two main types—primary motor and sensory areas and association areas.