Aging, grey matter, and blood flow in the anterior cingulate cortex

Area of Science:

• Neuroscience
• Aging Research
• Cognitive Neuroscience

Background:

• The anterior cingulate cortex (ACC) integrates emotion and cognition, vital for decision-making.
• Aging impacts ACC function, but interpretation is complicated by structural changes like reduced grey matter volume and altered cerebral vasculature.
• Understanding ACC functional changes in aging is key to explaining late-life psychological shifts.

Purpose of the Study:

• To investigate the relationship between aging, ACC blood flow, and ACC grey matter volume.
• To examine how age-related changes in blood flow and grey matter volume interact within different ACC subregions.

Main Methods:

• Acquired high-resolution structural MRI and quantitative [15O]water positron emission tomography (PET) blood flow imaging in 26 healthy adults (25-79 years).
• Traced ACC regions (dorsal, rostral, subgenual) on MRI data.
• Analyzed correlations between age, ACC blood flow, and ACC grey matter volume, including mediation analysis.

Main Results:

• A negative correlation was found between age and blood flow in the dorsal and rostral ACC.
• A similar, though weaker, trend was observed in the subgenual ACC.
• Older age and lower blood flow were associated with smaller rostral ACC grey matter volumes, with grey matter volume partially mediating the age effect on blood flow.

Conclusions:

• Aging is associated with reduced blood flow in key ACC subregions.
• Grey matter volume partially mediates the relationship between age and blood flow in the rostral ACC.
• The findings suggest potential neural alterations or that reduced blood flow may precede grey matter volume reduction in the ACC.