Document Detail


Multimodal Magnetic Resonance Imaging Assessment of White Matter Aging Trajectories Over the Lifespan of Healthy Individuals.
MedLine Citation:
PMID:  23017471     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
BACKGROUND: Postmortem and volumetric imaging data suggest that brain myelination is a dynamic lifelong process that, in vulnerable late-myelinating regions, peaks in middle age. We examined whether known regional differences in axon size and age at myelination influence the timing and rates of development and degeneration/repair trajectories of white matter (WM) microstructure biomarkers. METHODS: Healthy subjects (n = 171) 14-93 years of age were examined with transverse relaxation rate (R(2)) and four diffusion tensor imaging measures (fractional anisotropy [FA] and radial, axial, and mean diffusivity [RD, AxD, MD, respectively]) of frontal lobe, genu, and splenium of the corpus callosum WM (FWM, GWM, and SWM, respectively). RESULTS: Only R(2) reflected known levels of myelin content with high values in late-myelinating FWM and GWM regions and low ones in early-myelinating SWM. In FWM and GWM, all metrics except FA had significant quadratic components that peaked at different ages (R(2) < RD < MD < AxD), with FWM peaking later than GWM. Factor analysis revealed that, although they defined different factors, R(2) and RD were the metrics most closely associated with each other and differed from AxD, which entered into a third factor. CONCLUSIONS: The R(2) and RD trajectories were most dynamic in late-myelinating regions and reflect age-related differences in myelination, whereas AxD reflects axonal size and extra-axonal space. The FA and MD had limited specificity. The data suggest that the healthy adult brain undergoes continual change driven by development and repair processes devoted to creating and maintaining synchronous function among neural networks on which optimal cognition and behavior depend.
Authors:
George Bartzokis; Po H Lu; Panthea Heydari; Alexander Couvrette; Grace J Lee; Greta Kalashyan; Frank Freeman; John W Grinstead; Pablo Villablanca; J Paul Finn; Jim Mintz; Jeffry R Alger; Lori L Altshuler
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-9-25
Journal Detail:
Title:  Biological psychiatry     Volume:  -     ISSN:  1873-2402     ISO Abbreviation:  Biol. Psychiatry     Publication Date:  2012 Sep 
Date Detail:
Created Date:  2012-9-28     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0213264     Medline TA:  Biol Psychiatry     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.
Affiliation:
Department of Psychiatry, The David Geffen School of Medicine at UCLA, Los Angeles, California; Laboratory of Neuroimaging, The David Geffen School of Medicine at UCLA, Los Angeles, California; Greater Los Angeles Veterans Administration Healthcare System, West Los Angeles, California. Electronic address: gbar@ucla.edu.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Identification of microRNAs as a potential novel regulatory mechanism in HSD11B1 expression.
Next Document:  An integrative review of factors related to patient satisfaction with general anesthesia care.