美国的医学研究发现，从脑部的运作可以说明为什么人的举止从40岁开始，就随着年龄的增长而缓慢下来。
以加州洛杉矶大学巴特佐基斯医生为首的研究小组在《老年神经生物学》杂志上发表报告说，人们进行抛球、转向、操控驾驶盘等动作的速度，是由脑细胞发出的指令传到肌肉所需时间的快慢来决定，也就是脑波如何快速传达出去。
新研究发现，即使是健康的人，只要一过40岁这不惑之年，脑部就会开始丧失一些传达信息的能力，丧失的速度非常缓慢。
巴特佐基斯医生指出，这说明了为什么很难找到年过40的世界级运动员。他说，人脑就像互联网，脑部的髓磷脂（myelin）有如互联网的速度宽带，健康的髓磷酯紧密围绕着神经纤维，迅速传达脑波。
试验结果显示，点击速度和髓磷脂健康的高峰期是39岁，过后随着年龄的增长而转弱。（生物谷Bioon.com）
生物谷推荐原始出处：
Neurobiology of Aging doi:10.1016/j.neurobiolaging.2008.08.015
Lifespan trajectory of myelin integrity and maximum motor speed
George Bartzokis, Po H. Lu, Kathleen Tingus, Mario F. Mendez, Aurore Richard, Douglas G. Peters, Bolanle Oluwadara, Katherine A. Barrall, J. Paul Finn, Pablo Villablanca, Paul M. Thompson, d and Jim Mintzf
Objective
Myelination of the human brain results in roughly quadratic trajectories of myelin content and integrity, reaching a maximum in mid-life and then declining in older age. This trajectory is most evident in vulnerable later myelinating association regions such as frontal lobes and may be the biological substrate for similar trajectories of cognitive processing speed. Speed of movement, such as maximal finger tapping speed (FTS), requires high-frequency action potential (AP) bursts and is associated with myelin integrity. We tested the hypothesis that the age-related trajectory of FTS is related to brain myelin integrity.
Methods
A sensitive in vivo MRI biomarker of myelin integrity (calculated transverse relaxation rates (R2)) of frontal lobe white matter (FLwm) was measured in a sample of very healthy males (N = 72) between 23 and 80 years of age. To assess specificity, R2 of a contrasting early-myelinating region (splenium of the corpus callosum) was also measured.
Results
FLwm R2 and FTS measures were significantly correlated (r = .45, p < .0001) with no association noted in the early-myelinating region (splenium). Both FLwm R2 and FTS had significantly quadratic lifespan trajectories that were virtually indistinguishable and both reached a peak at 39 years of age and declined with an accelerating trajectory thereafter.
Conclusions
The results suggest that in this very healthy male sample, maximum motor speed requiring high-frequency AP burst may depend on brain myelin integrity. To the extent that the FLwm changes assessed by R2 contribute to an age-related reduction in AP burst frequency, it is possible that other brain functions dependent on AP bursts may also be affected. Non-invasive measures of myelin integrity together with testing of basic measures of processing speed may aid in developing and targeting anti-aging treatments to mitigate age-related functional declines.
