Editing Putamen (section)

===Substantia nigra===
The substantia nigra contains two parts: the substantia nigra pars compacta (SNpc) and the substantia nigra pars reticulata (SNpr). The SNpc obtains input from the putamen and caudate, and sends information back. The SNpr also obtains input from the putamen and caudate. However, it sends the input outside the basal ganglia to control head and [[Eye movement (sensory)|eye movement]]s. The SNpc produces dopamine, which is crucial for movements. The SNpc degenerates during [[Parkinson's disease]].<ref name="Alexander">{{cite journal | journal =  Trends in Neurosciences|date=July 1990 | volume = 13 | issue = 7 | pages = 266–71 | title = Functional architecture of basal ganglia circuits: neural substrates of parallel processing | author = Alexander GE |author2=Crutcher MD  | pmid = 1695401 | doi =10.1016/0166-2236(90)90107-L |s2cid=3990601 }}</ref>