Editing Subthalamic nucleus (section)

=== Structure ===
The principal type of [[neuron]] found in the subthalamic nucleus has rather long, sparsely spiny [[dendrite]]s.<ref name=Afsharpour1985>{{cite journal | vauthors = Afsharpour S | title = Light microscopic analysis of Golgi-impregnated rat subthalamic neurons | journal = The Journal of Comparative Neurology | volume = 236 | issue = 1 | pages = 1–13 | date = June 1985 | pmid = 4056088 | doi = 10.1002/cne.902360102 | s2cid = 12482772 }}</ref><ref>{{cite journal | vauthors = Rafols JA, Fox CA | title = The neurons in the primate subthalamic nucleus: a Golgi and electron microscopic study | journal = The Journal of Comparative Neurology | volume = 168 | issue = 1 | pages = 75–111 | date = July 1976 | pmid = 819471 | doi = 10.1002/cne.901680105 | s2cid = 11962279 }}</ref> In the more centrally located neurons, the dendritic arbors have a more [[ellipsoid]]al shape.<ref>{{cite journal | vauthors = Yelnik J, Percheron G | title = Subthalamic neurons in primates: a quantitative and comparative analysis | journal = Neuroscience | volume = 4 | issue = 11 | pages = 1717–1743 | year = 1979 | pmid = 117397 | doi = 10.1016/0306-4522(79)90030-7 | s2cid = 40909863 }}</ref> The dimensions of these arbors (1200&nbsp;μm, 600&nbsp;μm, and 300&nbsp;μm) are similar across many species—including rat, cat, monkey and human—which is unusual. However, the number of neurons increases with brain size as well as the external dimensions of the nucleus. The principal neurons are [[glutamatergic]], which give them a particular functional position in the basal ganglia system. In humans there are also a small number (about 7.5%) of [[GABA]]ergic [[interneuron]]s that participate in the local circuitry; however, the dendritic arbors of subthalamic neurons shy away from the border and primarily interact with one another.<ref>{{cite journal | vauthors = Lévesque JC, Parent A | title = GABAergic interneurons in human subthalamic nucleus | journal = Movement Disorders | volume = 20 | issue = 5 | pages = 574–584 | date = May 2005 | pmid = 15645534 | doi = 10.1002/mds.20374 | s2cid = 9551517 }}</ref>

The structure of the subthalamic nucleus has not yet been fully explored and understood, but it is likely composed of several internal domains. The primate subthalamic nucleus is often divided in three internal anatomical-functional domains. However, this so-called ''tripartite model'' has been debated because it does not fully explain the complexity of the subthalamic nucleus in brain function.<ref>{{cite journal | vauthors = Alkemade A, Forstmann BU | title = Do we need to revise the tripartite subdivision hypothesis of the human subthalamic nucleus (STN)? | journal = NeuroImage | volume = 95 | pages = 326–329 | date = July 2014 | pmid = 24642281 | doi = 10.1016/j.neuroimage.2014.03.010 | s2cid = 11010595 }}</ref><ref>{{cite journal | vauthors = Lambert C, Zrinzo L, Nagy Z, Lutti A, Hariz M, Foltynie T, Draganski B, Ashburner J, Frackowiak R | title = Confirmation of functional zones within the human subthalamic nucleus: patterns of connectivity and sub-parcellation using diffusion weighted imaging | journal = NeuroImage | volume = 60 | issue = 1 | pages = 83–94 | date = March 2012 | pmid = 22173294 | pmc = 3315017 | doi = 10.1016/j.neuroimage.2011.11.082 }}</ref>