Scale-free behavioral dynamics directly linked with scale-free cortical dynamics

Naturally occurring body movements and collective neural activity both exhibit complex dynamics, often with scale-free, fractal spatiotemporal structure, thought to confer functional benefits to the organism. Despite their similarities, scale-free brain activity and scale-free behavior have been studied separately, without a unified explanation. Here we show that scale-free dynamics of behavior and certain subsets of cortical neurons are one-to-one related. Surprisingly, the scale-free neural subsets exhibit stochastic winner-take-all competition with other neural subsets, inconsistent with prevailing theory of scale-free neural systems. We develop a computational model which accounts for known cell-type-specific circuit structure and explains our findings. Our results establish neural underpinnings of scale-free behavior and clear behavioral relevance of scale-free neural activity, which was previously thought to represent background noise in cerebral cortex.