The organization of sensory cortex

Recent studies of primary visual cortex (VI) redefine layers 3 and 4 of V1 in monkeys and show that monkeys, apes and humans have different laminar sp ecializations. Projections from V1 define a smaller, but complete, third vi sual area, and a dorsomedial area. The middle temporal visual area has two types of motion-sensitive modules with inputs, from. cytochrome oxidase col umns in V1. Second-level somatosensory areas have been described in humans, and a second-level auditory area is shown to respond to somatosensory stim uli.