Editing Lateral geniculate nucleus (section)

==Rodents==

In rodents, the lateral geniculate nucleus contains the dorsal lateral geniculate nucleus (dLGN), the ventral lateral geniculate nucleus (vLGN), and the region in between called the intergeniculate leaflet (IGL). These are distinct subcortical nuclei with differences in function.

===dLGN===

The dorsolateral geniculate nucleus is the main division of the lateral geniculate body. In the mouse, the area of the dLGN is about 0.48mm<math>{}^2</math>. The majority of input to the dLGN comes from the retina. It is laminated and shows retinotopic organization.<ref>{{cite journal|last=Grubb|first=Matthew S. |author2=Francesco M. Rossi |author3=Jean-Pierre Changeux |author4=Ian D. Thompson|title=Abnormal functional organization in the dorsal lateral geniculate nucleus of mice lacking the beta2 subunit of the nicotinic acetylcholine receptor|journal=Neuron|date=Dec 18, 2003|volume=40|issue=6|pages=1161–1172|doi=10.1016/s0896-6273(03)00789-x|pmid=14687550|doi-access=free}}</ref>

===vLGN===

The ventrolateral geniculate nucleus has been found to be relatively large in several species such as lizards, rodents, cows, cats, and primates.<ref>{{cite journal|last=Cooper|first=H.M.|author2=M. Herbin |author3=E. Nevo |title=Visual system of a naturally microphthalamic mammal: The blind mole rat, Spalax ehrenbergl|journal=Journal of Comparative Neurology|date=Oct 9, 2004|volume=328|issue=3|pages=313–350|doi=10.1002/cne.903280302|pmid=8440785|s2cid=28607983}}</ref>  An initial cytoarchitectural scheme, which has been confirmed in several studies, suggests that the vLGN is divided into two parts. The external and internal divisions are separated by a group of fine fibers and a zone of thinly dispersed neurons. Additionally, several studies have suggested further subdivisions of the vLGN in other species.<ref name="Harrington 1997 705–727">{{cite journal|last=Harrington|first=Mary|title=The ventral lateral geniculate nucleus and the intergeniculate leaflet: interrelated structures in the visual and circadian systems|journal=Neuroscience and Biobehavioral Reviews|date=1997|volume=21|issue=5|pages=705–727|doi=10.1016/s0149-7634(96)00019-x|pmid=9353800|s2cid=20139828}}</ref> For example, studies indicate that the cytoarchitecture of the vLGN in the cat differs from rodents. Although five subdivisions of the vLGN in the cat have been identified by some,<ref>{{cite journal|last=Jordan|first=J.|author2=H. Hollander |title=The structure of the ventral part of the lateral geniculate nucleus – a cyto- and myeloarchitectonic study in the cat|journal= Journal of Comparative Neurology|date=1972|volume=145|issue=3|pages=259–272|doi=10.1002/cne.901450302|pmid=5030906|s2cid=30586321}}</ref>  the scheme that divides the vLGN into three regions (medial, intermediate, and lateral) has been more widely accepted.

===IGL===

The intergeniculate leaflet is a relatively small area found dorsal to the vLGN. Earlier studies had referred to the IGL as the internal dorsal division of the vLGN. Several studies have described homologous regions in several species, including humans.<ref>{{cite journal|last=Moore|first=Robert Y.|title=The geniculohypothalamic tract in monkey and man|journal=Brain Research|date=1989|volume=486|pages=190–194|doi=10.1016/0006-8993(89)91294-8|pmid=2720429|issue=1|s2cid=33543381}}</ref>

The vLGN and IGL appear to be closely related based on similarities in neurochemicals, inputs and outputs, and physiological properties.

The vLGN and IGL have been reported to share many neurochemicals that are found concentrated in the cells, including neuropeptide Y, GABA, encephalin, and nitric oxide synthase. The neurochemicals serotonin, acetylcholine, histamine, dopamine, and noradrenaline have been found in the fibers of these nuclei.

Both the vLGN and IGL receive input from the retina, locus coreuleus, and raphe. Other connections that have been found to be reciprocal include the superior colliculus, pretectum, and hypothalamus, as well as other thalamic nuclei.

Physiological and behavioral studies have shown spectral-sensitive and motion-sensitive responses that vary with species. The vLGN and IGL seem to play an important role in mediating phases of the circadian rhythms that are not involved with light, as well as phase shifts that are light-dependent.<ref name="Harrington 1997 705–727"/>