Critical point dynamics in whole-Brain neuronal activity

Ponce-Alvarez et al., Whole-Brain Neuronal Activity Displays Crackling Noise Dynamics, Neuron (2018), https://doi.org/10.1016/j.neuron.2018.10.045.

Highlights

• Zebrafish whole-brain activity displays scale-invariant neuronal avalanches 

• These scale-invariant avalanches are suggestive of critical phenomena 

• Sensory inputs and self-generated behaviors deviate the dynamics from criticality 

• Blocking gap junctions disrupts criticality and deteriorates sensory processing

Summary

Previous studies suggest that the brain operates at a critical point in which phases of order and disorder coexist, producing emergent patterned dynamics at all scales and optimizing several brain functions. Here, we combined light-sheet microscopy with GCaMP zebrafish larvae to study whole-brain dynamics in vivo at near single-cell resolution. We show that spontaneous activity propagates in the brain’s three-dimensional space, generating scale-invariant neuronal avalanches with time courses and recurrence times that exhibit statistical self-similarity at different magnitude, temporal, and frequency scales. This suggests that the nervous system operates close to a non-equilibrium phase transition, where a large repertoire of spatial, temporal, and interactive modes can be supported. Finally, we show that gap junctions contribute to the maintenance of criticality and that, during interactions with the environment (sensory inputs and self-generated behaviors), the system is transiently displaced to a more ordered regime, conceivably to limit the potential sensory representations and motor outcomes.