Changes in topological organization of functional PET brain network with normal aging

Area of Science:

• Neuroscience
• Network Science
• Gerontology

Background:

• Normal aging is linked to changes in large-scale brain functional and structural systems.
• Age-related alterations in functional brain networks derived from positron emission tomography (PET) data are not well understood.

Purpose of the Study:

• To investigate age-related changes in functional brain networks using PET data.
• To compare network properties between younger and older healthy adults.

Main Methods:

• Functional brain networks were constructed from PET data of 113 younger (mean age 36.5) and 110 older (mean age 56.3) adults.
• Network analysis employed graph theory on 90 brain regions, examining correlation matrices of cerebral glucose metabolism.
• Robustness against random failures and targeted attacks was assessed.

Main Results:

• Both age groups exhibited small-world network architecture.
• Older adults displayed increased clustering and decreased network efficiency, suggesting a shift towards a more regular network structure.
• Altered nodal centralities were observed, particularly in association and paralimbic cortex regions (e.g., orbitofrontal cortex, hippocampus).
• Older networks were similarly robust to random failures but more vulnerable to targeted attacks compared to younger networks.

Conclusions:

• Normal aging is associated with a topological shift in functional brain networks, moving from small-world to regular architectures.
• Changes in nodal centrality in specific brain regions reflect age-related neural alterations.
• Functional brain network alterations in aging impact network resilience.