Editing White matter (section)

==Research==
[[Multiple sclerosis]] (MS) is the most common of the [[inflammatory demyelinating diseases of the central nervous system]] which affect white matter. In MS lesions, the [[myelin]] sheath around the [[axons]] is deteriorated by [[inflammation]].<ref name="hoft">{{cite book | last1=Höftberger | first1=Romana | last2=Lassmann | first2=Hans | title=Handbook of Clinical Neurology | chapter=Inflammatory demyelinating diseases of the central nervous system | volume=145 | publisher=Elsevier | year=2018 | isbn=978-0-12-802395-2 | issn=0072-9752 | doi=10.1016/b978-0-12-802395-2.00019-5 | pmid=28987175 | pages=263–283| pmc=7149979 }}</ref> [[Alcohol use disorder]]s are associated with a decrease in white matter volume.<ref>{{cite journal |doi=10.1111/j.1369-1600.2012.00441.x |pmid=22458455 |pmc=3390447 |title=White matter volume in alcohol use disorders: A meta-analysis |journal=Addiction Biology |volume=18 |issue=3 |pages=581–592 |year=2013 |last1=Monnig |first1=Mollie A. |last2=Tonigan |first2=J. Scott |last3=Yeo |first3=Ronald A. |last4=Thoma |first4=Robert J. |last5=McCrady |first5=Barbara S. }}</ref>

[[Amyloid plaques]] in white matter may be associated with [[Alzheimer's disease]] and other [[neurodegenerative disease]]s.<ref name="Rose">{{cite journal | last1=Roseborough | first1=Austyn | last2=Ramirez | first2=Joel | last3=Black | first3=Sandra E. | last4=Edwards | first4=Jodi D. | title=Associations between amyloid β and white matter hyperintensities: A systematic review | journal=Alzheimer's & Dementia | volume=13 | issue=10 | year=2017 | issn=1552-5260 | doi=10.1016/j.jalz.2017.01.026 | pages=1154–1167|pmid=28322203| s2cid=35593591 }}</ref> Other changes that commonly occur with age include the development of [[leukoaraiosis]], which is a rarefaction of the white matter that can be correlated with a variety of conditions, including loss of myelin pallor, axonal loss, and diminished restrictive function of the [[blood–brain barrier]].<ref>{{Cite journal|last=O'Sullivan|first=M.|date=2008-01-01|title=Leukoaraiosis|journal=Practical Neurology|language=en|volume=8|issue=1|pages=26–38|doi=10.1136/jnnp.2007.139428|issn=1474-7758|pmid=18230707|s2cid=219190542}}</ref>

There is also evidence that substance abuse may damage white matter microstructure, though prolonged abstinence may in certain cases reverse such white matter changes.<ref name=Hamp2019>{{cite journal | vauthors = Hampton WH, Hanik I, Olson IR | title = [Substance Abuse and White Matter: Findings, Limitations, and Future of Diffusion Tensor Imaging Research] | language = en | journal = Drug and Alcohol Dependence | volume = 197 | issue = 4 | pages = 288–298 | year = 2019 | pmid = 30875650 | pmc = 6440853 | doi = 10.1016/j.drugalcdep.2019.02.005 | quote = Given that our the central nervous system is an intricately balanced, complex network of billions of neurons and supporting cells, some might imagine that extrinsic substances could cause irreversible brain damage. Our review paints a less gloomy picture of the substances reviewed, however. Following prolonged abstinence, abusers of alcohol (Pfefferbaum et al., 2014) or opiates (Wang et al., 2011) have white matter microstructure that is not significantly different from non-users. There was also no evidence that the white matter microstructural changes observed in longitudinal studies of cannabis, nicotine, or cocaine were completely irreparable. It is therefore possible that, at least to some degree, abstinence can reverse effects of substance abuse on white matter. The ability of white matter to "bounce back" very likely depends on the level and duration of abuse, as well as the substance being abused.}}</ref>

[[White matter lesion]]s on magnetic resonance imaging are linked to several adverse outcomes, such as [[cognitive impairment]] and [[Mood disorders|depression]].<ref name="OBrien 2014 pp. 133–137">{{cite journal | last=O'Brien | first=John T. | title=Clinical Significance of White Matter Changes | journal=The American Journal of Geriatric Psychiatry | publisher=Elsevier BV | volume=22 | issue=2 | year=2014 | issn=1064-7481 | doi=10.1016/j.jagp.2013.07.006 | pmid=24041523 | pages=133–137}}</ref> [[White matter hyperintensity|White matter hyperintensities]] are often found in patients with [[vascular dementia]], particularly with small vessel/subcortical subtypes of vascular dementia.<ref name="Hirono Kitagaki Kazui Hashimoto 2000 pp. 2182–2188">{{cite journal | last1=Hirono | first1=Nobutsugu | last2=Kitagaki | first2=Hajime | last3=Kazui | first3=Hiroaki | last4=Hashimoto | first4=Mamoru | last5=Mori | first5=Etsuro | title=Impact of White Matter Changes on Clinical Manifestation of Alzheimer's Disease | journal=Stroke | publisher=Ovid Technologies (Wolters Kluwer Health) | volume=31 | issue=9 | year=2000 | issn=0039-2499 | doi=10.1161/01.str.31.9.2182 | pmid=10978049 | pages=2182–2188| doi-access=free }}</ref>

===Volume===

Smaller volumes (in terms of group averages) of white matter might be associated with larger deficits in [[attention]], [[declarative memory]], [[executive function]]s, [[intelligence]], and [[academic achievement]].<ref name="Tasman 2015 p. ">{{cite book | last=Tasman | first=Allan | title=Psychiatry | publisher=Wiley Blackwell | location=West Sussex, England | year=2015 | isbn=978-1-118-84549-3 | oclc=903956524 | language=cy }}</ref><ref name="Fields 2008 pp. 361–370">{{cite journal | last=Fields | first=R. Douglas | title=White matter in learning, cognition and psychiatric disorders | journal=Trends in Neurosciences | publisher=Elsevier BV | volume=31 | issue=7 | date=2008-06-05 | issn=0166-2236 | pmid=18538868 | pmc=2486416 | doi=10.1016/j.tins.2008.04.001 | pages=361–370}}</ref> However, volume change is continuous throughout one's lifetime due to [[neuroplasticity]], and is a contributing factor rather than determinant factor of certain functional deficits due to compensating effects in other brain regions.<ref name="Fields 2008 pp. 361–370"/> The integrity of white matter declines due to aging.<ref name="Handbook of the Psychology of Aging 2016 p. ">{{cite book | title=Handbook of the Psychology of Aging | publisher=Elsevier | year=2016 | isbn=978-0-12-411469-2 | doi=10.1016/c2012-0-07221-3 }}</ref> Nonetheless, regular [[aerobic exercise]] appears to either postpone the aging effect or in turn enhance the white matter integrity in the long run.<ref name="Handbook of the Psychology of Aging 2016 p. "/> Changes in white matter volume due to inflammation or injury may be a factor in the severity of [[obstructive sleep apnea]].<ref name="Castronovo Scifo Castellano Aloia pp. 1465–1475">{{cite journal | last1=Castronovo | first1=Vincenza | last2=Scifo | first2=Paola | last3=Castellano | first3=Antonella | last4=Aloia | first4=Mark S. | last5=Iadanza | first5=Antonella | last6=Marelli | first6=Sara | last7=Cappa | first7=Stefano F. | last8=Strambi | first8=Luigi Ferini | last9=Falini | first9=Andrea | title=White Matter Integrity in Obstructive Sleep Apnea before and after Treatment | journal=Sleep | volume=37 | issue=9 | date=2014-09-01 | issn=0161-8105 | pmid=25142557 | pmc=4153061 | doi=10.5665/sleep.3994 | pages=1465–1475}}</ref><ref name="Chen Lu Lin Chen pp. 361–370">{{cite journal | last1=Chen | first1=Hsiu-Ling | last2=Lu | first2=Cheng-Hsien | last3=Lin | first3=Hsin-Ching | last4=Chen | first4=Pei-Chin | last5=Chou | first5=Kun-Hsien | last6=Lin | first6=Wei-Ming | last7=Tsai | first7=Nai-Wen | last8=Su | first8=Yu-Jih | last9=Friedman | first9=Michael | last10=Lin | first10=Ching-Po | last11=Lin | first11=Wei-Che | title=White Matter Damage and Systemic Inflammation in Obstructive Sleep Apnea | journal=Sleep| volume=38 | issue=3 | date=2015-03-01 | issn=0161-8105 | pmid=25325459 | pmc=4335530 | doi=10.5665/sleep.4490 | pages=361–370}}</ref>