How networks communicate: propagation patterns in spontaneous brain activity.

Area of Science:

• Neuroscience
• Systems Neuroscience
• Cognitive Neuroscience

Background:

• Spontaneous brain activity constitutes a significant metabolic cost.
• Infra-slow (<0.1 Hz) spontaneous activity, measured by resting-state functional magnetic resonance imaging (fMRI) blood oxygen level-dependent (BOLD) signals, shows correlations within resting state networks (RSNs).
• The temporal organization of spontaneous BOLD fluctuations remains poorly understood.

Purpose of the Study:

• To investigate the temporal dynamics and organization of spontaneous BOLD signal fluctuations.
• To elucidate how spontaneous activity patterns contribute to the formation of RSNs.
• To understand how physiological and pathological states alter spontaneous brain activity propagation.

Main Methods:

• Analysis of temporal lags in resting-state BOLD signals.
• Identification of reproducible whole-brain propagation patterns in spontaneous BOLD fluctuations.
• Characterization of unidirectional 'motifs' within propagation patterns.

Main Results:

• Spontaneous BOLD fluctuations exhibit reproducible whole-brain propagation patterns.
• Unidirectional 'motifs' are embedded within these propagation patterns, giving rise to RSNs.
• Propagation patterns are significantly altered by physiological and pathological states.

Conclusions:

• Spontaneous BOLD activity has a structured temporal organization characterized by whole-brain propagation.
• Understanding these propagation patterns offers deeper insights into brain function in health and disease.
• This research contributes to interpreting BOLD signals in dialogue between cognitive and cellular neuroscience.