Criticality

Over the last 20 years, neuroimaging and electrophysiology techniques have become central to understanding the mechanisms that accompany loss and recovery of consciousness. Much of this research is performed in the context of healthy individuals with neurotypical brain dynamics. Yet, a true understanding of how consciousness emerges from the joint action of neurons has to account for how severely pathological brains, often showing phenotypes typical of unconsciousness, can nonetheless generate a subjective viewpoint. In this presentation, I will start from the context of Disorders of Conscious

…and possible relationships among criticality, sleep and neural manifolds, drawing on their review of the experimental literature.

…criticisms and the question of whether criticality is a distinctive computational property of brains or part of a broader natural phenomenon.

…is that cortex operates close to criticality, i.e., close to a boundary between two different dynamical regimes. At criticality, flu

The critical brain hypothesis proposes that neural networks operate near criticality to reap the computational benefits of accessing a wide range of timescales [1]. Proponents of this viewpoint highlight the presence of heavy-tailed (power-law) spatiotemporal correlations as markers of criticality in the brain [2]. Critics of this hypothesis argue that such correlations could be inherited from upstream sources, such as sensory input [3]. Similarly, Ref. [4] constructed a model of independent neurons driven by shared noise input that exhibited neural activity with power-law tails, which could b

…accurate measures of the distance to criticality (DTC). Many existing metrics of criticality---such as increased signal variance and slower timescales---are derived from analytically tractable systems with fixed or low-amplitude dynamical noise. However, the brain is highly stochastic, with noise levels that can vary between regions, recordings, or indivi

…representations operate closer to criticality, where external

…the other side, different distances to criticality were inferred from the recordings of nervous systems. In my talk, I discuss how including additional constraints on the processing time can shift the optimal operating point of the recurrent networks. Moreover, the data from the visual cortex of the monkeys during the attentional task indicate that they flexibly change the closeness to the criti

…that cortical dynamics are near criticality. Criticality is often studied in neural systems as a non-equilibrium thermodynamic process in which scale-free patterns of activity, called avalanches, emerge between distinct states of spontaneous activity. W