Scale-free brain activity: past, present, and future.

Area of Science:

• Neuroscience
• Complex Systems
• Signal Processing

Background:

• Brain activity across multiple scales, from neuronal potentials to EEG, MEG, and fMRI, exhibits a 1/f-like power spectrum.
• This scale-free characteristic indicates arrhythmic brain activity without a dominant temporal scale, differentiating it from brain oscillations.
• Despite coexisting with oscillations, the understanding of scale-free brain activity remains limited.

Purpose of the Study:

• To review recent advancements in understanding scale-free brain activity.
• To highlight the spatiotemporal organization, functional significance, and generative mechanisms of this prevalent brain signal.
• To underscore the developmental and clinical relevance of scale-free brain activity.

Main Methods:

• Review of recent scientific literature on scale-free brain activity.
• Analysis of power spectrum properties in various brain signals (EEG, MEG, fMRI, etc.).
• Synthesis of findings on spatiotemporal organization and functional significance.

Main Results:

• Scale-free brain activity is a fundamental property observed across diverse spatiotemporal scales and measurement techniques.
• Recent research has elucidated its organization, function, and underlying mechanisms.
• Developmental and clinical relevance of scale-free dynamics are increasingly recognized.

Conclusions:

• A comprehensive understanding of scale-free brain activity is crucial for advancing cognitive neuroscience.
• This prevalent brain signal offers potential for new analytical tools and insights.
• Further research into scale-free dynamics can bridge gaps in our knowledge of brain function.