Structural damage-driven brain compensation among near-centenarians and centenarians without dementia

Area of Science:

• Neuroscience
• Cognitive Aging
• Neuroimaging

Background:

• Compensation mechanisms are proposed to explain preserved cognition in advanced age.
• Increased functional connectivity is a known compensatory mechanism for age-related white matter damage.
• Direct investigation of these mechanisms in the very old population is lacking.

Purpose of the Study:

• To investigate the relationship between functional connectivity, cognitive preservation, and white matter damage in near-centenarians and centenarians.
• To explore how structural brain disconnections relate to preserved cognitive functioning in extreme old age.

Main Methods:

• Examined a cohort of 44 individuals aged 95-103 years without dementia.
• Constructed a structural disconnection matrix based on white matter hyperintensities (WMHs) disrupting white matter pathways.
• Analyzed the relationship between structural damage, functional connectivity patterns, and cognitive performance.

Main Results:

• Structural brain damage reliably explained variations in functional connectivity and cognitive maintenance.
• Significant positive correlations were observed between brain disconnection models and cognitive function.
• Strongest correlations included attention and somatomotor network (SMN), memory and SMN, fluency and visual (VIS)-control network (CN), language and VIS, visuospatial ability and VIS-default mode network (DMN), and global cognition and VIS-DMN.

Conclusions:

• Enhanced functional connectivity appears to be a compensatory mechanism mitigating white matter damage effects.
• This compensatory mechanism contributes to preserved cognitive performance in very old age.
• Findings highlight the brain's adaptability in maintaining cognitive function despite aging-related structural changes.