Fig. 12 Parallel processing in the primate visual system. LGN, lateral geniculate nucleus; Magnosystem: high-contrast sensitivity, low spatial frequency, motion stereopsis. MT, middle temporal cortex; Parvosystem: low-contrast sensitivity, high spatial frequency, color. V1, striate cortex (area 17); V2, parastriate cortex (area 18); V3 and V4, extrastriate cortex.