Connectivity trajectory across lifespan differentiates the precuneus from the default network.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Brain Imaging

Background:

• The default network's role in cognition and disorders is known, but its components and boundaries, especially the precuneus, remain debated.
• Understanding age-related changes in brain networks is crucial for development and aging studies.

Purpose of the Study:

• To investigate lifespan trajectories of intrinsic functional brain networks using functional magnetic resonance imaging (fMRI).
• To clarify the relationship and differential aging patterns between the default network and a precuneus-based network.

Main Methods:

• Utilized Generalized Ranking and Averaging Independent Component Analysis by Reproducibility (gRAICAR) on a cross-lifespan fMRI dataset (N=126, ages 7-85).
• Estimated individual-specific spatial components and aligned them across subjects to measure population-level spatial variation.
• Performed post-hoc functional connectivity analyses to confirm network trajectories.

Main Results:

• Observed stronger age dependence in the spatial pattern of the precuneus-dorsal posterior cingulate cortex network compared to the default network.
• Found that these two networks tend to merge with increasing age.
• Confirmed distinguishable cross-lifespan trajectories between the precuneus and default networks.

Conclusions:

• Proposed a dynamic model of cross-lifespan functional segregation and integration between the precuneus and default networks.
• Suggested the precuneus network may have a distinct functional role compared to the default network, which shows age-related decline.
• Highlighted implications for understanding brain disorders and aging processes.