Regional Brain Changes in Aging Healthy Adults: General Trends, Individual Differences and Modifiers

Abstract

Brain aging research relies mostly on cross-sectional studies, which infer true changes from age differences. We present longitudinal measures of five-year change in the regional brain volumes in healthy adults. Average and individual differences in volume changes and the effects of age, sex and hypertension were assessed with latent difference score modeling. The caudate, the cerebellum, the hippocampus and the association cortices shrunk substantially. There was minimal change in the entorhinal and none in the primary visual cortex. Longitudinal measures of shrinkage exceeded cross-sectional estimates. All regions except the inferior parietal lobule showed individual differences in change. Shrinkage of the cerebellum decreased from young to middle adulthood, and increased from middle adulthood to old age. Shrinkage of the hippocampus, the entorhinal cortices, the inferior temporal cortex and the prefrontal white matter increased with age. Moreover, shrinkage in the hippocampus and the cerebellum accelerated with age. In the hippocampus, both linear and quadratic trends in incremental age-related shrinkage were limited to the hypertensive participants. Individual differences in shrinkage correlated across some regions, suggesting common causes. No sex differences in age trends except for the caudate were observed. We found no evidence of neuroprotective effects of larger brain size or educational attainment.

Gray Matter Changes in Late Life Depression—a Structural MRI Analysis

“…Manual measurements of intracranial volume or the use of height/body mass index as a proxy for the intracranial volume can be unreliable for the elderly population (Rosano et al, 2007). Moreover, different gray matter structures (frontal areas, medial temporal areas) have a non-linear age-related variability, rendering the use of the whole gray matter volume as control less accurate (Raz et al, 2005). AlsoFin this specific sampleFthe whole brain was larger in the depressed subjects than in the comparison subjects.…”

Motion‐related artifacts in structural brain images revealed with independent estimates of in‐scanner head motion

“…We suggest that these effects may in some cases be overestimated, particularly in certain brain locations, by the inclusion of biased estimates from T1w structural scans with motion artifacts. The present work leveraged the variability in head motion and morphometry in a healthy adult sample to show that: (1) independent estimates of motion significantly predicted GM thickness (independent of age and gender), and (2) motion slightly but significantly biased thickness estimates in several regions that are often highlighted to undergo cortical thinning with increasing age [e.g., medial PFC, cingulate cortex, precuneus, IFG and anterior insula, SMG, lateral temporal cortex; Fjell et al, 2009; Lemaitre et al, 2012; Raz et al, 2005; Salat et al, 2004; Storsve et al, 2014]. …”

Relationships between cardiorespiratory fitness, hippocampal volume, and episodic memory in a population at risk for Alzheimer's disease

“…However, when examining the sample split by gender, the negative association only remained for the women. Although the propensity of the literature supports similar age‐related hippocampal volume loss for men and women (Jack et al., 2015; Mu, Xie, Wen, Weng, & Shuyun, 1999; Raz et al., 2004, 2005), there are reports of both women‐ and men‐specific age–hippocampal volume relationships (Murphy et al.,1996; Pruessner et al., 2001). For the current sample, the lack of significant association in the men may be explained by this gender not experiencing a similar age‐related trajectory in hippocampal volume, and therefore not experiencing the benefits of CRF on hippocampal volume.…”