Editing Lateral geniculate nucleus (section)

==Ipsilateral and contralateral layers==
Both the LGN in the right hemisphere and the LGN in the left hemisphere receive input from each eye. However, each LGN only receives information from one half of the visual field. [[Retinal ganglion cell]]s (RGCs) from the inner halves of each retina (the nasal sides) [[Decussation|decussate]] (cross to the other side of the brain) through the [[optic chiasma]] (''khiasma'' means "cross-shaped"). RGCs from the outer half of each retina (the temporal sides) remain on the same side of the brain. Therefore, the right LGN receives visual information from the left visual field, and the left LGN receives visual information from the right visual field. Within one LGN, the visual information is divided among the various layers as follows:<ref>Nicholls J., ''et al.'' ''From Neuron to Brain: Fourth Edition''. Sinauer Associates, Inc. 2001.</ref>
* the eye on the same side (the ''ipsilateral'' eye) sends information to layers 2, 3 and 5
* the eye on the opposite side (the ''contralateral'' eye) sends information to layers 1, 4 and 6.

This description applies to the LGN of many primates, but not all. The sequence of layers receiving information from the ipsilateral and contralateral (opposite side of the head) eyes is different in the [[tarsier]].<ref>{{cite journal|last1=Rosa|first1=MG|last2=Pettigrew|first2=JD|last3=Cooper|first3=HM|title=Unusual pattern of retinogeniculate projections in the controversial primate Tarsius|journal=Brain, Behavior and Evolution|date=1996|volume=48|issue=3|pages=121–9|pmid=8872317|doi=10.1159/000113191}}</ref> Some neuroscientists suggested that "this apparent difference distinguishes tarsiers from all other primates, reinforcing the view that they arose in an early, independent line of primate evolution".<ref>{{cite journal|last1=Collins|first1=CE|last2=Hendrickson|first2=A|last3=Kaas|first3=JH|title=Overview of the visual system of Tarsius|journal=The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology|date=Nov 2005|volume=287|issue=1|pages=1013–25|pmid=16200648|doi=10.1002/ar.a.20263|doi-access=free}}</ref>