Spontaneous physiological variability modulates dynamic functional connectivity in resting-state functional magnetic...

Area of Science:

• Neuroimaging
• Physiological monitoring
• Brain connectivity

Background:

• The blood oxygen level-dependent (BOLD) signal in functional magnetic resonance imaging (fMRI) is affected by neuronal activity and physiological fluctuations (e.g., arterial CO2, heart rate).
• Spontaneous physiological variations can regionally influence BOLD signals and confound resting-state functional connectivity estimates.
• Resting functional connectivity is dynamic, but the sources of its temporal variations remain unclear.

Purpose of the Study:

• To investigate the relationship between time-varying physiological signals and dynamic functional connectivity patterns during rest.
• To understand how physiological fluctuations modulate brain network connectivity over time.

Main Methods:

• Resting-state fMRI data were acquired from 12 healthy subjects.
• Simultaneous recordings of physiological signals, including end-tidal CO2 and heart rate/heart rate variability (HR/HRV), were obtained.
• Discrete wavelet decomposition was used to analyze signal frequencies.

Main Results:

• Physiological signals (end-tidal CO2, HR/HRV) significantly modulated dynamic functional connectivity patterns in several resting-state networks (default mode, somatosensory, visual).
• These modulatory effects were found to be frequency-dependent, with specific bands showing more pronounced influence.
• The study identified links between physiological variability and dynamic changes in brain network interactions.

Conclusions:

• Physiological fluctuations are significant contributors to the dynamic nature of resting-state functional connectivity.
• Understanding these physiological influences is crucial for accurate interpretation of fMRI-based brain connectivity studies.
• Targeting specific frequency bands may offer insights into the physiological modulation of brain networks.