Fig. 4

Retinal ganglion cell (RGC) pathways in the human brain. Visual information travels from each retina through the optic nerve and converges at the optic chiasm. Uncrossed ipsilateral inputs connect to L2, L3, and L5 in the lateral geniculate nucleus, whereas crossed contralateral inputs connect to L1, L4, and L6 in the lateral geniculate nucleus. Both ipsilateral and contralateral inputs connect to the suprachiasmatic nucleus, olivary pretectal nucleus, and superior colliculus. Intrinsically photosensitive RGCs (ipRGCs), among others, connect to the neurons in the suprachiasmatic nucleus and olivary pretectal nucleus (green) to regulate circadian rhythms and the pupillary light reflex, respectively. Parasol RGCs, among others, connect to the neurons in the superior colliculus (purple) to orient head and eye movements and to L1 and L2 in the lateral geniculate nucleus as a part of the magnocellular pathway (purple). Midget RGCs, among others, connect to the neurons in L3, L4, L5, and L6 of the lateral geniculate nucleus as a part of the parvocellular pathway (pink). The magnocellular and parvocellular pathways connect to the visual cortex to primarily process motion and high-contrast information, respectively