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. 2021 Dec 24;9(2):e1126. doi: 10.1212/NXI.0000000000001126

Figure 1. Afferent Visual System Anatomy.

Figure 1

(A) Phototransduction occurs in photoreceptor cells in the outer retina. These visual signals are processed and transmitted by horizontal and bipolar cells residing in the inner nuclear layer (INL). Bipolar cell axons form synapses with the dendrites of retinal ganglion cells (RGCs) in the inner plexiform retinal layer. The optic nerve is formed by the unmyelinated axons of RGCs, tracking along the inner retinal surface in the nerve fiber layer (RNFL) and converging at the optic nerve head. Subjacent to the ganglion cell layer (GCL), the INL consists of the bipolar, horizontal, and amacrine cells as well the cell bodies of astrocytic Müller cells. (B) Beyond the cribiform plate, the RGC axons of the optic nerve are myelinated and travel approximately 4 cm to the optic chiasm. The optic nerve partially decussates at the chiasm: The axons from the contralateral nasal and ipsilateral temporal hemiretinas join to form the optic tract (OT). The OT carries visual signals to the thalamic lateral geniculate nucleus (LGN). The secondary LGN neurons project to the primary visual cortex through the optic radiations (OR). From the primary visual cortex, projections go through the extrastriate cortex of the occipital lobe to the parietal lobe (the dorsal pathway for visually guided movements) and the temporal lobe (the ventral pathway for object recognition). Parts of the figure are provided by courtesy of neurodial.de (neurodial.de/2017/08/25/schematic-figure-retina-creative-commons-license/).