Heterogeneity of Synaptic Input Connectivity Regulates Spike-based Neuronal Avalanches

TL;DR

This study uses computational models to explore how different types of synaptic connectivity heterogeneity influence neuronal avalanche dynamics, revealing that input heterogeneity plays a key regulatory role.

Contribution

It demonstrates that input heterogeneity, but not output heterogeneity, modulates neuronal avalanches and cortical activity in network models, providing insights into structural regulation of brain dynamics.

Findings

Input heterogeneity triggers neuronal avalanches at intermediate levels.

Output heterogeneity does not evoke avalanche dynamics.

Criticality and oscillations are modulated by input heterogeneity.

Abstract

Our mysterious brain is believed to operate near a non-equilibrium point and generate critical self-organized avalanches in neuronal activity. Recent experimental evidence has revealed significant heterogeneity in both synaptic input and output connectivity, but whether the structural heterogeneity participates in the regulation of neuronal avalanches remains poorly understood. By computational modelling, we predict that different types of structural heterogeneity contribute distinct effects on avalanche neurodynamics. In particular, neuronal avalanches can be triggered at an intermediate level of input heterogeneity, but heterogeneous output connectivity cannot evoke avalanche dynamics. In the criticality region, the co-emergence of multi-scale cortical activities is observed, and both the avalanche dynamics and neuronal oscillations are modulated by the input heterogeneity. Remarkably, we show similar results can be reproduced in networks with various types of in- and out-degree distributions. Overall, these findings not only provide details on the underlying circuitry mechanisms of nonrandom synaptic connectivity in the regulation of neuronal avalanches, but also inspire testable hypotheses for future experimental studies.