Coupling between Blood Pressure and Subarachnoid Space Width Oscillations during Slow Breathing

Area of Science:

• Neuroscience
• Cardiovascular Physiology
• Biophysics

Background:

• The precise mechanisms linking the cardiovascular system and cerebrospinal fluid (CSF) dynamics remain incompletely understood.
• Investigating these interactions is crucial for understanding brain health and disease.

Purpose of the Study:

• To investigate the coupling between cardiac and respiratory components of blood pressure (BP) and subarachnoid space (SAS) width.
• To explore how slow breathing and inspiratory resistance affect these physiological couplings.

Main Methods:

• Utilized wavelet transform for signal analysis of BP and SAS oscillations.
• Employed dynamical Bayesian inference for the first time to determine phase connectivity and coupling functions between BP and SAS signals.
• Collected data from 20 healthy volunteers during controlled ventilation protocols.

Main Results:

• Slow breathing, with or without inspiratory resistance, significantly increased coupling strength between respiratory and cardiac components in both BP and SAS signals.
• Observed enhanced coupling between the respiratory component of BP and the cardiac component of SAS (and vice versa).
• Slow breathing synchronized SAS oscillations between brain hemispheres, while inspiratory resistance partially reversed this effect.

Conclusions:

• BP-SAS and SAS-BP interactions are modulated by respiratory patterns, suggesting alterations in overall brain biomechanical properties.
• Findings provide novel insights into the dynamic interplay between cardiovascular and cerebrospinal fluid systems.
• This research establishes a new method for quantifying inter-system physiological couplings.