Editing Striatum (section)

===Cell types===
[[File:Dendritic spines.jpg|thumb|180px|[[Dendritic spine]]s on [[medium spiny neuron]] of striatum]]
Types of cells in the striatum include:
* [[Medium spiny neurons]] (MSNs), which are the principal neurons of the striatum.<ref name=YAGER2015 /> They are [[GABAergic]] and, thus, are classified as inhibitory neurons. Medium spiny projection neurons comprise 95% of the total neuronal population of the human striatum.<ref name=YAGER2015 />  Medium spiny neurons have two [[phenotype|characteristic types]]: [[D1-type]] MSNs and [[D2-type]] MSNs.<ref name=YAGER2015 /><ref name=FERRE2010 /><ref name="MSN 40% mixed-type with DRD1 and DRD2" /> A subpopulation of MSNs contain both D1-type and D2-type receptors, with approximately&nbsp;40% of striatal MSNs expressing both [[DRD1]] and [[DRD2]] [[Messenger RNA|mRNA]].<ref name=YAGER2015 /><ref name=FERRE2010 /><ref name="MSN 40% mixed-type with DRD1 and DRD2">{{cite journal |last1=Nishi |first1=Akinori |last2=Kuroiwa |first2=Mahomi |last3=Shuto |first3=Takahide |title=Mechanisms for the Modulation of Dopamine D1 Receptor Signaling in Striatal Neurons |journal=Frontiers in Neuroanatomy |date=2011 |volume=5 |pages=43 |doi=10.3389/fnana.2011.00043 |pmid=21811441 |pmc=3140648 |doi-access=free }}</ref>
* [[acetylcholine|Cholinergic]] [[interneurons]] release acetylcholine, which has a variety of important effects in the striatum. In humans, other primates, and rodents, these interneurons respond to salient environmental stimuli with stereotyped responses that are temporally aligned with the responses of dopaminergic neurons of the [[substantia nigra]].<ref>{{cite journal |last1=Goldberg |first1=J.A. |last2=Reynolds |first2=J.N.J. |title=Spontaneous firing and evoked pauses in the tonically active cholinergic interneurons of the striatum |journal=Neuroscience |date=December 2011 |volume=198 |pages=27–43 |doi=10.1016/j.neuroscience.2011.08.067 |pmid=21925242 |s2cid=21908514 }}</ref><ref>{{cite journal |last1=Morris |first1=Genela |last2=Arkadir |first2=David |last3=Nevet |first3=Alon |last4=Vaadia |first4=Eilon |last5=Bergman |first5=Hagai |title=Coincident but Distinct Messages of Midbrain Dopamine and Striatal Tonically Active Neurons |journal=Neuron |date=July 2004 |volume=43 |issue=1 |pages=133–143 |doi=10.1016/j.neuron.2004.06.012 |pmid=15233923 |doi-access=free }}</ref> The large aspiny cholinergic interneurons themselves are affected by dopamine through [[dopamine receptor D5|D5 dopamine receptors]].<ref>{{cite journal |last1=Bergson |first1=C |last2=Mrzljak |first2=L |last3=Smiley |first3=JF |last4=Pappy |first4=M |last5=Levenson |first5=R |last6=Goldman-Rakic |first6=PS |title=Regional, cellular, and subcellular variations in the distribution of D1 and D5 dopamine receptors in primate brain |journal=The Journal of Neuroscience |date=1 December 1995 |volume=15 |issue=12 |pages=7821–7836 |doi=10.1523/JNEUROSCI.15-12-07821.1995 |pmid=8613722 |pmc=6577925 }}</ref> Dopamine also directly controls communication between cholinergic interneurons.<ref>{{cite journal |last1=Raz |first1=Aeyal |title=Neuronal synchronization of tonically active neurons in the striatum of normal and parkinsonian primates |journal=Journal of Neurophysiology |date=1996 |volume=76 |issue=3 |pages=2083–2088 |doi=10.1152/jn.1996.76.3.2083 |pmid=8890317}}</ref><ref>{{cite journal |last1=Dorst |first1=Matthijs |title=Polysynaptic inhibition between striatal cholinergic interneurons shapes their network activity patterns in a dopamine-dependent manner |journal=Nature Communications |date=2020 |volume=11 |issue=1 |page=5113 |doi=10.1038/s41467-020-18882-y |pmid=33037215 |pmc=7547109 |bibcode=2020NatCo..11.5113D }}</ref>
* There are many types of GABAergic interneurons.<ref name="Ibáñez-Sandoval O. Front Neuroanat 2010"/> The best known are [[parvalbumin]] expressing interneurons, also known as [[Action potential|fast-spiking]] interneurons, which participate in powerful [[feed forward (control)|feedforward]] inhibition of principal neurons.<ref>{{cite journal |last1=Koós |first1=Tibor |last2=Tepper |first2=James M. |title=Inhibitory control of neostriatal projection neurons by GABAergic interneurons |journal=Nature Neuroscience |date=May 1999 |volume=2 |issue=5 |pages=467–472 |doi=10.1038/8138 |pmid=10321252 |s2cid=16088859 }}</ref> Also, there are GABAergic interneurons that express [[tyrosine hydroxylase]],<ref>{{cite journal |last1=Ibanez-Sandoval |first1=O. |last2=Tecuapetla |first2=F. |last3=Unal |first3=B. |last4=Shah |first4=F. |last5=Koos |first5=T. |last6=Tepper |first6=J. M. |title=Electrophysiological and Morphological Characteristics and Synaptic Connectivity of Tyrosine Hydroxylase-Expressing Neurons in Adult Mouse Striatum |journal=Journal of Neuroscience |date=19 May 2010 |volume=30 |issue=20 |pages=6999–7016 |doi=10.1523/JNEUROSCI.5996-09.2010 |pmid=20484642 |pmc=4447206 }}</ref> [[somatostatin]], [[nitric oxide synthase]] and [[Neuropeptide Y|neuropeptide-y]]. Recently, two types of neuropeptide-y expressing GABAergic interneurons have been described in detail,<ref>{{cite journal |last1=Ibanez-Sandoval |first1=O. |last2=Tecuapetla |first2=F. |last3=Unal |first3=B. |last4=Shah |first4=F. |last5=Koos |first5=T. |last6=Tepper |first6=J. M. |title=A Novel Functionally Distinct Subtype of Striatal Neuropeptide Y Interneuron |journal=Journal of Neuroscience |date=16 November 2011 |volume=31 |issue=46 |pages=16757–16769 |doi=10.1523/JNEUROSCI.2628-11.2011 |pmid=22090502 |pmc=3236391 }}</ref> one of which translates synchronous activity of cholinergic interneurons into inhibition of principal neurons.<ref>{{cite journal |last1=English |first1=Daniel F |last2=Ibanez-Sandoval |first2=Osvaldo |last3=Stark |first3=Eran |last4=Tecuapetla |first4=Fatuel |last5=Buzsáki |first5=György |last6=Deisseroth |first6=Karl |last7=Tepper |first7=James M |last8=Koos |first8=Tibor |title=GABAergic circuits mediate the reinforcement-related signals of striatal cholinergic interneurons |journal=Nature Neuroscience |date=11 December 2011 |volume=15 |issue=1 |pages=123–130 |doi=10.1038/nn.2984 |pmid=22158514 |pmc=3245803 }}</ref> These [[neuron]]s of the striatum are not distributed evenly.<ref name="Ibáñez-Sandoval O. Front Neuroanat 2010">{{cite journal |last1=Tepper |first1=James M. |last2=Tecuapetla |first2=Fatuel |last3=Koós |first3=Tibor |last4=Ibáñez-Sandoval |first4=Osvaldo |title=Heterogeneity and Diversity of Striatal GABAergic Interneurons |journal=Frontiers in Neuroanatomy |date=2010 |volume=4 |pages=150 |doi=10.3389/fnana.2010.00150 |pmid=21228905 |pmc=3016690 |doi-access=free }}</ref>

There are two regions of [[neurogenesis]] in the brain – the [[subventricular zone]] (SVZ) in the [[lateral ventricle]]s, and the [[dentate gyrus]] in the [[hippocampal formation]].  [[Neuroblast]]s that form in the lateral ventricle adjacent to the striatum, integrate in the striatum.<ref name="Ernst">{{cite journal|last1=Ernst|first1=Aurélie|last2=Alkass|first2=Kanar|last3=Bernard|first3=Samuel|last4=Salehpour|first4=Mehran|last5=Perl|first5=Shira|last6=Tisdale|first6=John|last7=Possnert|first7=Göran|last8=Druid|first8=Henrik|last9=Frisén|first9=Jonas|title=Neurogenesis in the Striatum of the Adult Human Brain|journal=Cell|date=February 2014|volume=156|issue=5|pages=1072–1083|doi=10.1016/j.cell.2014.01.044|pmid=24561062|doi-access=free}}</ref><ref>{{cite journal|last1=Inta|first1=D|last2=Lang|first2=U E|last3=Borgwardt|first3=S|last4=Meyer-Lindenberg|first4=A|last5=Gass|first5=P|title=Adult neurogenesis in the human striatum: possible implications for psychiatric disorders|journal=Molecular Psychiatry|date=16 February 2016|volume=21|issue=4|pages=446–447|doi=10.1038/mp.2016.8|pmid=26878892|doi-access=free}}</ref> This has been noted in the human striatum following an [[Stroke#Ischemic|ischemic stroke]]. Injury caused to the striatum stimulates the migration of neuroblasts from the SVZ, to the striatum, where they differentiate into adult neurons.<ref name="Kernie">{{cite journal|last1=Kernie|first1=SG|last2=Parent|first2=JM|title=Forebrain neurogenesis after focal Ischemic and traumatic brain injury.|journal=Neurobiology of Disease|date=February 2010|volume=37|issue=2|pages=267–74|pmid=19909815|doi=10.1016/j.nbd.2009.11.002|pmc=2864918}}</ref> The normal passage of SVZ neuroblasts is to the [[olfactory bulb]] but this traffic is diverted to the striatum after an ischemic stroke. However, few of the new developed neurons survive.<ref name="SVZ">{{cite journal|last1=Yamashita|first1=T|last2=Ninomiya|first2=M|last3=Hernández Acosta|first3=P|last4=García-Verdugo|first4=JM|last5=Sunabori|first5=T|last6=Sakaguchi|first6=M|last7=Adachi|first7=K|last8=Kojima|first8=T|last9=Hirota|first9=Y|last10=Kawase|first10=T|last11=Araki|first11=N|last12=Abe|first12=K|last13=Okano|first13=H|last14=Sawamoto|first14=K|title=Subventricular zone-derived neuroblasts migrate and differentiate into mature neurons in the post-stroke adult striatum.|journal=The Journal of Neuroscience|date=14 June 2006|volume=26|issue=24|pages=6627–36|pmid=16775151|doi=10.1523/jneurosci.0149-06.2006|pmc=6674034|url=http://ousar.lib.okayama-u.ac.jp/files/public/1/11746/20160527190854209485/K003322.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://ousar.lib.okayama-u.ac.jp/files/public/1/11746/20160527190854209485/K003322.pdf |archive-date=2022-10-09 |url-status=live}}</ref>