Collective neural dynamics and information processing

The human brain has amazing information processing capacity, which relies on the activity of 80 billion neurons, each of them interacting with thousands of other neurons. However, their collective dynamics and the origin of their information processing capacities remain unknown. A popular hypothesis is that the neural network self-organizes to a critical state, because in models this state showed maximal processing capacities (quantified as information storage and transfer). However, I showed recently that in vivo spike recordings from rats, cats and monkeys indicated consistently a subcritical regime instead of criticality. Moreover, the ‘distance to criticality’ changed from wakefulness to deep sleep. I suggest that the brain changes its distance to criticality depending on needs: In general, it maintaining a variable safety margin to criticality, because criticality comes with the risk of runaway activity (epilepsy), but it reduces the safety margin temporarily when high processing capacities are needed.