Researchers at Federal University of Pernambuco in Brazil have carried out the first measurements of “criticality” — which occurs in systems that are delicately balanced between inactivity, where the changes are always small, to a state of overactivity where any change tends to be runaway.neuronal avalanche distribution — in animals carrying out tasks and throughout their full sleep-wake cycle.

Ribeiro say their results show clear evidence of criticality throughout this cycle. The research suggests that brains are optimized for the encoding of memory patterns across all natural states. “Indeed, the results are compatible with the hypothesis that individual memories are encoded by specific spike avalanches,” they say. The result will help to build consensus that the brain operates in a remarkable, delicately balanced state.