Generalized Cortical Branching Model: A Minimal Functional Network of Brain Dynamics

Spiking time raster plots of ensemble of cortical neurons show complex patterns. Neuronal avalanche analysis on those activity patterns indicates that brains operate close to critical point (quasicriticality). The Cortical Branching Model (CBM), a minimal cellular automaton model consisting solely of excitatory neurons, can reproduce effective critical exponents and the scaling relation of observed data. Here we present a generalized CBM (GCBM) to include inhibitory neurons. While generalization is not straightforward, this minimal model can capture two ubiquitous salient features of raster plots: brief network bursts among many neurons (vertical raster stripes) and individual neurons that seem to fire continuously for long intervals (horizontal raster stripes). By matching both the spike raster and the effective scaling relation, the GCBM can shed some light on the roles of inhibitory neurons in brain dynamics.