Functional MRI Signatures of Autonomic Physiology in Aging

Area of Science:

• Neuroscience
• Physiology
• Medical Imaging

Background:

• Blood-oxygen-level-dependent (BOLD) functional MRI (fMRI) signals, often dismissed as noise, reflect systemic physiology like heart rate and respiration.
• These physiological fluctuations offer insights into brain vascular properties and autonomic nervous system function.
• Understanding age-related changes in these physiological signals is crucial for brain health research.

Purpose of the Study:

• To investigate age-related alterations in the spatiotemporal BOLD-fMRI signatures of autonomic physiology (heart rate and respiration).
• To characterize how brain vascular properties and autonomic function change with advancing age.
• To identify potential biomarkers for aging using resting-state fMRI.

Main Methods:

• Utilized a large dataset from the Lifespan Human Connectome Project Aging study.
• Analyzed resting-state BOLD-fMRI data to extract physiological signatures of heart rate and respiratory variation.
• Investigated the relationship between age and physiological fMRI signal characteristics.

Main Results:

• Aging is associated with globally slower respiratory fMRI responses and faster cardiac fMRI responses.
• Enhanced coupling between brain signals and cardiac activity was observed with aging.
• A significant turning point in age-related physiological fMRI signal changes was identified after age 60.

Conclusions:

• Significant age effects are evident in the fMRI signatures of systemic physiology, highlighting altered vascular properties and autonomic function in aging.
• Resting-state fMRI can extract multi-parametric physiological information, offering novel biomarker opportunities.
• These findings emphasize the importance of considering physiological BOLD signals for understanding brain aging.