Year: 2008
Type: article
Study design: Observational Study
Abstract: Myelination of the human brain results in roughly quadratic trajectories of myelin 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 depends on myelin integrity. The hypothesis that the age-related trajectory of FTS depends on brain myelin integrity was tested using an in vivo MRI biomarker of myelin integrity (calculated transverse relaxation rates (R2)) of frontal lobe white matter (FLwm) in a sample of healthy males (N=72) between 23 and 80 years of age. To assess specificity, R2 of a contrasting early-myelinating region was also measured. FLwm R2 and FTS measures were significantly correlated (r=.45, p<.0001) with no association noted in the early-myelinating region. 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. We suggest that motor and other brain functions that require high-frequency AP burst (such as long term potentiation (LTP)) may depend on myelin integrity. Non-invasive measures of myelin integrity together with testing of basic measures of processing speed may aid in developing and targeting anti-aging treatments that mitigate age-related functional declines.
Source: Alzheimer s & Dementia
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W1994847621