Neutral theory and scale-free neural dynamics

Abstract

Avalanches of electrochemical activity in brain networks have been empirically reported to obey scale-invariant behavior --characterized by power-law distributions up to some upper cut-off-- both in vitro and in vivo. Elucidating whether such scaling laws stem from the underlying neural dynamics operating at the edge of a phase transition is a fascinating possibility, as systems poised at criticality have been argued to exhibit a number of important functional advantages. Here we employ a well-known model for neural dynamics with synaptic plasticity, to elucidate an alternative scenario in which neuronal avalanches can coexist, overlapping in time, but still remaining scale-free. Remarkably their scale-invariance does not stem from underlying criticality nor self-organization at the edge of a continuous phase transition. Instead, it emerges from the fact that perturbations to the system exhibit a neutral drift --guided by demographic fluctuations-- with respect to endogenous spontaneous activity. Such a neutral dynamics --similar to the one in neutral theories of population genetics-- implies marginal propagation of activity, characterized by power-law distributed causal avalanches. Importantly, our results underline the importance of considering causal information --on which neuron triggers the firing of which-- to properly estimate the statistics of avalanches of neural activity. We discuss the implications of these findings both in modeling and to elucidate experimental observations, as well as its possible consequences for actual neural dynamics and information processing in actual neural networks.

Main text: 8 pages, 3 figures. Supplementary information: 5 pages, 4 figures

References in corpus (5)

• Emergent complex neural dynamics
• Dynamical synapses causing self-organized criticality in neural networks
• Stochastic Models of Evolution in Genetics, Ecology and Linguistics
• Langevin description of critical phenomena with two symmetric absorbing states
• A simple unified view of branching process statistics: random walks in balanced logarithmic potentials

Cited by in corpus (27)

• Colloquium: Criticality and dynamical scaling in living systems
• Self-organization toward criticality by synaptic plasticity
• Hysteresis, neural avalanches and critical behaviour near a first-order transition of a spiking neural network
• Feedback mechanisms for self-organization to the edge of a phase transition
• Homeostatic plasticity and external input shape neural network dynamics
• Hybrid-type synchronization transitions: where marginal coherence, scale-free avalanches, and bistability live together
• Time-series thresholding and the definition of avalanche size
• Hopf Bifurcation in Mean Field Explains Critical Avalanches in Excitation-Inhibition Balanced Neuronal Networks: A Mechanism for Multiscale Variability
• Theoretical foundations of studying criticality in the brain
• Mutual information disentangles interactions from changing environments
• Testing the critical brain hypothesis using a phenomelogical renormalization group
• Criticality in spreading processes without time-scale separation and the critical brain hypothesis
• First-passage distributions for the one-dimensional Fokker-Planck equation
• Disentangling the critical signatures of neural activity
• Critical neuronal models with relaxed timescales separation
• Description of spreading dynamics by microscopic network models and macroscopic branching processes can differ due to coalescence
• Robustness of Griffiths effects in homeostatic connectome models
• Bridging the information and dynamics attributes of neural activities
• Measuring neuronal avalanches in disordered systems with absorbing states
• Emergent spatial patterns of coexistence in species-rich plant communities
• The Concealed Voter Model is in the Voter Model universality class
• Neutral Theory for competing attention in social networks
• Random search with resetting in heterogeneous environments
• Random-search efficiency in a bounded interval with spatially heterogeneous diffusion coefficient
• Scaling of causal neural avalanches in a neutral model
• Anomalous finite-size scaling in higher-order processes with absorbing states
• Memory-cognizant generalization to Simon's random-copying neutral model