Transient brain-wide coactivations and structured transitions revealed in hemodynamic imaging data

Area of Science:

• Neuroimaging
• Systems Neuroscience
• Physiological Measurement

Background:

• Resting-state functional connectivity (FC) and brain states are key research areas in neuroimaging.
• Previous studies often use windowed timeframes and correlation-based methods to analyze FC.
• Hemodynamic signals are increasingly recognized for their relevance to neuronal activity.

Purpose of the Study:

• To investigate recurring transient brain-wide patterns in spontaneous hemodynamic fluctuations using high-density diffuse optical tomography (DOT).
• To analyze these patterns at the resolution of single timeframes in healthy adults at rest.
• To explore the spatiotemporal dynamics and transitions of these identified brain states.

Main Methods:

• Utilized novel whole-head cap-based high-density diffuse optical tomography (DOT).
• Applied data-driven analysis methods to hemodynamic signal data from thirteen healthy adults.
• Investigated spontaneous fluctuations at single-timeframe resolution to identify coactivation patterns (CAPs).

Main Results:

• Identified six distinct brain-wide coactivation patterns (CAPs) representing recurring brain states.
• Observed hemispheric symmetry and highly anticorrelated pairs within CAPs.
• Found structured transitions among CAPs, with two anterior-posterior patterns mediating state changes.
• Elucidated global positive and negative patterns reflecting cortical co- and deactivations.
• Demonstrated CAPs' role in generating peaks and troughs in global signals (GS).

Conclusions:

• Transient neuronal events (CAPs), global brain activity, and structured transitions coexist and are interconnected in the human brain.
• Findings extend observations of similar neuronal events in animal hemodynamic data.
• Future research should explore quantitative relationships between CAPs, windowed FC, and clinical conditions with larger sample sizes.