title: Brain modularity controls the critical behavior of spontaneous activity.
abstract: The human brain exhibits a complex structure made of scale-free highly connected modules loosely interconnected by weaker links to form a small-world network. These features appear in healthy patients whereas neurological diseases often modify this structure. An important open question concerns the role of brain modularity in sustaining the critical behaviour of spontaneous activity. Here we analyse the neuronal activity of a model, successful in reproducing on non-modular networks the scaling behaviour observed in experimental data, on a modular network implementing the main statistical features measured in human brain. We show that on a modular network, regardless the strength of the synaptic connections or the modular size and number, activity is never fully scale-free. Neuronal avalanches can invade different modules which results in an activity depression, hindering further avalanche propagation. Critical behaviour is solely recovered if inter-module connections are added, modifying the modular into a more random structure.
authors.affiliation: Physics Department, University of Naples Federico II, Napoli, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Russo
authors.affiliation: 1] Institute Computational Physics for Engineering Materials, ETH, Zürich, CH [2] Departamento de Física, Universidade Federal do Ceará, 60451-970 Fortaleza, Ceará, Brazil.
authors.forename: H J
authors.initials: HJ
authors.lastname: Herrmann
authors.affiliation: Department of Industrial and Information Engineering, Second University of Naples and INFN Gr. Coll. Salerno, Aversa (CE), Italy.
authors.forename: L
authors.initials: L
authors.lastname: de Arcangelis
mesh_terms: D001519:Behavior / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D009415:Nerve Net / Q000502:physiology*