Cerebral functional connectivity and Mayer waves in mice: Phenomena and separability

Area of Science:

• Neuroscience
• Physiology
• Biomedical Engineering

Background:

• Resting-state functional connectivity (RSFC) analyzes spontaneous brain activity using low-frequency hemodynamics (<0.08 Hz).
• Other low-frequency oscillations, vasomotion and Mayer waves (0.1–0.4 Hz), also occur in the brain.
• The relationship between Mayer waves and RSFC is not well understood.

Purpose of the Study:

• To investigate the coexistence and potential interference of Mayer waves with RSFC.
• To determine if RSFC patterns can be reliably extracted in the presence of Mayer waves.
• To explore methods for separating these distinct hemodynamic phenomena.

Main Methods:

• Optical intrinsic signal imaging was used to analyze spontaneous hemodynamic fluctuations in the mouse cortex.
• Data analysis involved examining hemodynamic signals within specific frequency bands.
• Bandpass filtering was applied to isolate different oscillatory components.

Main Results:

• Spontaneous hemodynamic oscillations around 0.2 Hz, consistent with Mayer waves, were observed.
• Significant variability in Mayer wave magnitude was noted across the mouse cohort.
• Functional connectivity patterns were successfully recovered from signals filtered to the 0.01–0.08 Hz band, irrespective of Mayer wave magnitude.

Conclusions:

• Mayer waves and RSFC can occur simultaneously in the brain.
• Bandpass filtering is an effective method for distinguishing between Mayer waves and RSFC signals.
• This finding supports the robust application of RSFC analysis even in the presence of Mayer waves.