Editing Visual system (section)

===Optic nerve===
{{Main|Optic nerve}}
[[File:1543,Vesalius'Fabrica,VisualSystem,V1.jpg|right|thumb|Information flow from the [[eye]]s (top), crossing at the [[optic chiasm]]a, joining left and right eye information in the [[optic tract]], and layering left and right visual stimuli in the [[lateral geniculate nucleus]]. [[Visual cortex#Primary visual cortex (V1)|V1]] in red at bottom of image.
(1543 image from [[Andreas Vesalius]]' ''Fabrica'')]]
The information about the image via the eye is transmitted to the brain along the [[optic nerve]].  Different populations of ganglion cells in the retina send information to the brain through the optic nerve. About 90% of the [[axons]] in the optic nerve go to the [[lateral geniculate nucleus]] in the [[thalamus]]. These axons originate from the M, P, and K ganglion cells in the retina, see above. This [[Parallel processing (psychology)|parallel processing]] is important for reconstructing the visual world; each type of information will go through a different route to [[perception]]. Another population sends information to the [[superior colliculus]] in the [[midbrain]], which assists in controlling eye movements ([[saccades]])<ref name="nolte">{{cite book |author1=Sundsten, John W. |author2=Nolte, John |title=The human brain: an introduction to its functional anatomy |publisher=Mosby |location=St. Louis |year=2001 |pages=410–447 |isbn=978-0-323-01320-8 |oclc=47892833 }}</ref> as well as other motor responses.

A final population of [[photosensitive ganglion cell]]s, containing [[melanopsin]] for [[photosensitivity]], sends information via the [[retinohypothalamic tract]] to the [[pretectum]] ([[pupillary reflex]]), to several structures involved in the control of [[circadian rhythms]] and [[sleep]] such as the [[suprachiasmatic nucleus]] (the biological clock), and to the [[ventrolateral preoptic nucleus]] (a region involved in [[sleep regulation]]).<ref>{{cite journal |vauthors=Lucas RJ, Hattar S, Takao M, Berson DM, Foster RG, Yau KW |title=Diminished pupillary light reflex at high irradiances in melanopsin-knockout mice |journal=Science |volume=299 |issue=5604 |pages=245–7 |date=January 2003 |pmid=12522249 |doi=10.1126/science.1077293 |bibcode=2003Sci...299..245L |citeseerx=10.1.1.1028.8525 |s2cid=46505800 }}</ref> A recently discovered role for photoreceptive ganglion cells is that they mediate conscious and unconscious vision – acting as rudimentary visual brightness detectors as shown in rodless coneless eyes.<ref name="Zaidi, 2007"/>