Brain modularity controls the critical behavior of spontaneous activity

Area of Science:

• Neuroscience
• Complex Systems
• Computational Biology

Background:

• The human brain features a complex, small-world network structure with highly connected modules.
• Neurological diseases often alter this intricate brain architecture.
• Understanding brain modularity's role in spontaneous activity is crucial.

Purpose of the Study:

• To investigate how brain modularity affects the critical behavior of neuronal activity.
• To analyze neuronal activity in a modular network model mirroring human brain statistics.

Main Methods:

• Utilized a computational model successfully reproducing scale-free behavior on non-modular networks.
• Applied the model to a modular network incorporating human brain statistical features.
• Examined neuronal activity patterns, avalanche propagation, and network connectivity.

Main Results:

• Modular networks, irrespective of connection strength or module characteristics, failed to exhibit fully scale-free activity.
• Neuronal avalanches were observed to cross modules, leading to activity depression and inhibited propagation.
• Critical behavior was only re-established upon introducing inter-module connections, promoting a more random network structure.

Conclusions:

• Strict modularity in brain networks suppresses scale-free critical activity.
• Inter-module connectivity is essential for maintaining the brain's critical dynamics.
• Network topology significantly influences the emergence and sustainability of complex brain activity patterns.