Editing White matter (section)

===Myelinated axon length===

One small study found that men have more white matter than women both in volume and in length of myelinated axons, and that volume and length reduced with age. (This study only included 36 participants.<ref>{{cite journal |doi=10.1002/cne.10714 |pmid=12794739 |title=Marked loss of myelinated nerve fibers in the human brain with age |journal=The Journal of Comparative Neurology |volume=462 |issue=2 |pages=144–152 |year=2003 |last1=Marner |first1=Lisbeth |last2=Nyengaard |first2=Jens R. |last3=Tang |first3=Yong |last4=Pakkenberg |first4=Bente |s2cid=35293796 }}</ref>) At the age of 20, the total length of myelinated fibers in men is 176,000&nbsp;km while that of a woman is 149,000&nbsp;km. There is a decline in total length with age of about 10% each decade such that a man at 80 years of age has 97,200&nbsp;km and a woman 82,000&nbsp;km. Most of this reduction is due to the loss of thinner fibers. However, this reduction may correlate with men having larger brains than women<ref>{{Cite web | url=https://www.nm.org/healthbeat/healthy-tips/battle-of-the-brain-men-vs-women-infographic#:~:text=Although%20the%20male%20brain%20is,alike%20than%20they%20are%20different | title=Battle of the Brain: Men Vs. Women | website=www.nm.org}}</ref>
and with brain size reducing with age.<ref>{{Cite web | url=https://www.publichealth.columbia.edu/news/changes-occur-aging-brain-what-happens-when-we-get-older#:~:text=By%20the%20age%20of%206,even%20more%20by%20age%2060 | title=Changes That Occur to the Aging Brain: What Happens When We Get Older | website=www.publichealth.columbia.edu| date=2021-06-10}}</ref>