Brain rhythms define distinct interaction networks with differential dependence on anatomy

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Computational Neuroscience

Background:

• Cognitive functions rely on synchronized neuronal activity across brain regions.
• Understanding how different neuronal rhythms contribute to functional connectivity is crucial.

Purpose of the Study:

• To investigate functional connectivity (FC) patterns associated with distinct neuronal rhythms (theta, beta, high-beta, gamma).
• To explore the relationship between functional interactions and anatomical connectivity.
• To identify network modularity and dominant rhythms within these networks.

Main Methods:

• Analyzed functional connectivity using coherence, power correlation, and Granger causality (GC) in 105 brain area pairs across four frequency bands.
• Correlated functional interaction metrics with anatomical projection strength in 91 area pairs.
• Examined spatial patterns of FC and rhythm strengths.

Main Results:

• Spatial patterns of functional connectivity were largely independent across different rhythms, indicating distinct interaction networks.
• Coherence and GC networks showed modular structures, often with a dominant rhythm per module.
• Anatomical projection strength was significantly related to coherence and GC, particularly for GC, with varying influence across rhythms (strongest for gamma, weakest for beta).

Conclusions:

• Neuronal rhythms organize into distinct functional networks that are largely independent of each other.
• Anatomical connectivity provides a common backbone that shapes these distinct functional networks, especially those identified by Granger causality.
• The influence of anatomy on functional connectivity varies significantly across different brain rhythms.