Trajectories of brain aging in middle-aged and older adults: Regional and individual differences

Abstract

The human brain changes with age. However, the rate and the trajectories of change vary among the brain regions and among individuals, and the reasons for these differences are unclear. In a sample of healthy middle-aged and older adults, we examined mean volume change and individual differences in the rate of change in 12 regional brain volumes over approximately 30 months. In addition to the baseline assessment, there were two follow-ups, 15 months apart. We observed significant average shrinkage of the hippocampus, entorhinal cortex, orbital-frontal cortex, and cerebellum in each of the intervals. Shrinkage of the hippocampus accelerated with time, whereas shrinkage of the caudate nucleus, prefrontal subcortical white matter, and corpus callosum emerged only at the second follow-up. Throughout both assessment intervals, the mean volumes of the lateral prefrontal and primary visual cortices, putamen, and pons did not change. Significant individual differences in shrinkage rates were observed in the lateral prefrontal cortex, the cerebellum, and all the white matter regions throughout the study, whereas additional regions (medialtemporal structures, the insula, and the basal ganglia) showed significant individual variation in change during the second follow-up. No individual variability was noted in the change of orbital frontal and visual cortices. In two white matter regions, we were able to identify factors associated with individual differences in brain shrinkage. In corpus callosum, shrinkage rate was greater in persons with hypertension, and in the pons, women and carriers of the ApoEε4 allele exhibited declines not noted in the whole sample.

Age-related changes in human and non-human primate white matter: from myelination disturbances to cognitive decline

“…Another study found a similar aging pattern that was observed over a 5-year period (Raz et al 2005). Moreover, WM loss in the prefrontal area of healthy old individuals was found to occur after only 30 months (Raz et al 2010), suggesting enhanced regional sensitivity to aging. The Baltimore Longitudinal Study reported age-related changes in MRIderived signal intensity, which was believed to reflect demyelination and changes in water, protein, and mineral content in the old (Davatzikos and Resnick 2002).…”

Monkeys that Voluntarily and Chronically Drink Alcohol Damage their Brains: a Longitudinal MRI Study

“…Age is an additional factor that leads to brain tissue volume decline in humans (Pfefferbaum et al, 1994;Pfefferbaum et al, 2013;Raz et al, 2010;Raz et al, 2005). The animals studied here ranged in age from 5.5 to 9.6 years at the beginning of the induction period, with a mean ± SD of 7.2 ± 1.6 years.…”

High-confidence memory errors in old age: The roles of monitoring and binding processes

“…Thus the propensity to confidently endorse novel events as experienced before is likely to reflect failures in executive and control functions implemented by frontal regions (Gilboa et al, 2006). In ageing, these brain regions are among the areas that undergo the strongest changes (Raz, Ghisletta, Rodrigue, Kennedy, & Lindenberger, 2010;Raz et al, 2005). Thus age-related increases in the propensity to false recognition with high subjective confidence may be related to deficits in the ability to carry out executive and monitoring operations confined to the PFC (Jacoby & Rhodes, 2006;Schacter et al, 1997).…”