Brain Characteristics of Individuals Resisting Age-Related Cognitive Decline over Two Decades

Abstract

Some elderly appear to resist age-related decline in cognitive functions, but the neural correlates of successful cognitive aging are not well known. Here, older human participants from a longitudinal study were classified as successful or average relative to the mean attritioncorrected cognitive development across 15-20 years in a population-based sample (n ϭ 1561). Fifty-one successful elderly and 51 age-matched average elderly (mean age: 68.8 years) underwent functional magnetic resonance imaging while performing an episodic memory face-name paired-associates task. Successful older participants had higher BOLD signal during encoding than average participants, notably in the bilateral PFC and the left hippocampus (HC). The HC activation of the average, but not the successful, older group was lower than that of a young reference group (n ϭ 45, mean age: 35.3 years). HC activation was correlated with task performance, thus likely contributing to the superior memory performance of successful older participants. The frontal BOLD response pattern might reflect individual differences present from young age. Additional analyses confirmed that both the initial cognitive level and the slope of cognitive change across the longitudinal measurement period contributed to the observed group differences in BOLD signal. Further, the differences between the older groups could not be accounted for by differences in brain structure. The current results suggest that one mechanism behind successful cognitive aging might be preservation of HC function combined with a high frontal responsivity. These findings highlight sources for heterogeneity in cognitive aging and may hold useful information for cognitive intervention studies.

Elevated hippocampal resting-state connectivity underlies deficient neurocognitive function in aging

“…We hypothesized that elevated connectivity of the HC RSN would negatively correlate with longitudinal decline in EM. To test this hypothesis, we compared individuals who maintained EM relatively intact over 20 y with individuals showing typical age-related decline (36). There was no significant difference (t < 0.6, p > 0.5) in head motion or age between the two groups.…”

“…2. HC RSN coupling in relation to longitudinal memory changes (36). Individuals (n = 51 subjects) who showed age-related decline over 20 y exhibited greater HC RSN coupling than their age-matched individuals (n = 51 subjects) who maintained episodic memory (age, 68.8 ± 7.1 y).…”

“…Such negative correlations could reflect an inability to flexibly recruit the HC and functionally associated areas during EM task performance due to aberrant hippocampal decoupling (23,24). We tested this prediction by relating the HC RSN, within-person, to HC recruitment during an EM fMRI task (35,36).…”

Better together: Left and right hemisphere engagement to reduce age-related memory loss

“…These findings drew attention to brain maintenance hypothesis [15]. According with the maintenance notion the brain of the old individuals whose cerebral anatomy is relatively preserved is more likely to exhibit functional brain activation patterns that appears similar to those of young subjects [92][93][94][95][96][97]. Moreover, less structural brain change is associated with better memory performance in old age.…”

β-Amyloid binding in elderly subjects with declining or stable episodic memory function measured with PET and [11C]AZD2184

“…There was also one subject in the stable group with family history of AD as opposed to no subjects with family history of AD in the declining group. Structural magnetic resonance imaging (MRI) had been performed in the Betula study, as part of a parallel functional MRI (fMRI) study [14], previous to inclusion in the present study.…”