Brain Aging and Its Modifiers
- 1 February 2007
- journal article
- review article
- Published by Wiley in Annals of the New York Academy of Sciences
- Vol. 1097 (1), 84-93
- https://doi.org/10.1196/annals.1379.018
Abstract
Aging is marked by individual differences and differential vulnerability of cognitive operations and their neural substrates. Cross‐sectional studies of brain volume reveal greater age‐related shrinkage of the prefrontal cortex (PFC) and the hippocampus than in the entorhinal and primary visual cortex. Longitudinal studies of regional brain shrinkage indicate that when individual differences are controlled, larger and broader shrinkage estimates are evident, with most polymodal cortices affected to the same extent. The mechanisms of age‐related shrinkage are unclear. Vascular risk factors may exacerbate brain aging and account for some of the observed declines as both the PFC and the hippocampus show elevated vulnerability to hypertension. MRI techniques that are sensitive to small vessels function, tissue oxygenation, and perfusion may be especially well suited to study brain aging and its vascular modifiers. We present an example of one such technique, susceptibility weighted imaging (SWI), that allows direct measurement of T2* values that reflect deoxy‐ to oxyhemoglobin fraction in blood vessels and iron deposits in cerebral tissue. The T2* shortening is associated with advanced age, but the effect is significantly stronger in the PFC and the hippocampus than the entorhinal and visual cortices. Moreover, T2* is shorter in hypertensive participants than in their matched normotensive counterparts, and the difference is especially prominent in the hippocampus, thus mirroring the findings of the neuromorphometric studies. Future research on brain aging would benefit from combining structural and metabolic techniques in a longitudinal design, as such studies will allow examination of leading–trailing effects of those factors.Keywords
This publication has 25 references indexed in Scilit:
- Age effects on atrophy rates of entorhinal cortex and hippocampusNeurobiology of Aging, 2006
- Study of the localization of iron, ferritin, and hemosiderin in Alzheimer’s disease hippocampus by analytical microscopy at the subcellular levelJournal of Structural Biology, 2006
- Noninvasive in vivo MRI detection of neuritic plaques associated with iron in APP[V717I] transgenic mice, a model for Alzheimer's diseaseMagnetic Resonance in Medicine, 2005
- Regional Brain Changes in Aging Healthy Adults: General Trends, Individual Differences and ModifiersCerebral Cortex, 2005
- Age does not increase rate of forgetting over weeks—Neuroanatomical volumes and visual memory across the adult life-spanJournal of the International Neuropsychological Society, 2005
- Correlation of R2 with total iron concentration in the brains of rhesus monkeysJournal of Magnetic Resonance Imaging, 2005
- Why voxel-based morphometric analysis should be used with great caution when characterizing group differencesNeuroImage, 2004
- Aging, sexual dimorphism, and hemispheric asymmetry of the cerebral cortex: replicability of regional differences in volumeNeurobiology of Aging, 2004
- Hypertension and the Brain: Vulnerability of the Prefrontal Regions and Executive Functions.Behavioral Neuroscience, 2003
- The correlation between phase shifts in gradient-echo MR images and regional brain iron concentrationMagnetic Resonance Imaging, 1999