Distance from main arteries influences microstructural and functional brain tissue characteristics

Area of Science:

• Neuroscience
• Medical Imaging
• Human Anatomy

Background:

• Neurons require a constant energy supply, making cerebral artery distribution critical.
• The proximity of brain tissue to major arteries may influence its microstructural and functional characteristics.

Purpose of the Study:

• To investigate if the distance from major cerebral arteries affects brain tissue microstructural and functional properties.
• To explore age-related changes in these distance-based gradients.

Main Methods:

• Utilized multimodal MRI in 102 healthy adults across the age span.
• Quantified microstructural properties using Relaxation along a fictitious field in the rotating frame of rank 4 (RAFF4), adiabatic T1ρ, T2ρ, and intracellular volume fraction (fICVF).
• Assessed functional metrics including degree centrality and fractional amplitude of low-frequency fluctuations.

Main Results:

• Found an inverse correlation between arterial distance and homogeneity for T1ρ, T2ρ, and RAFF4 in cortical grey and white matter.
• Observed microstructural differences between brain tissue near and far from arteries.
• Functional metrics indicated increased connectivity and neuronal activity farther from arteries, though with greater variability.
• Noted that age diminished these distance-based gradients, suggesting age-related tissue uniformization.

Conclusions:

• Brain regionalization based on arterial distance is a novel concept with potential biological underpinnings.
• This pilot study highlights significant microstructural and functional variations related to arterial proximity.
• Further research is warranted to validate these findings and elucidate the underlying biological mechanisms.