Whole-Brain Neuronal Activity Displays Crackling Noise Dynamics

Area of Science:

• Neuroscience
• Complex Systems
• Computational Biology

Background:

• The brain's functional dynamics are hypothesized to operate at a critical point, balancing order and disorder for optimal function.
• This critical state allows for emergent patterned dynamics across various scales, enhancing information processing.

Purpose of the Study:

• To investigate whole-brain dynamics in vivo at near single-cell resolution using light-sheet microscopy and GCaMP zebrafish larvae.
• To determine if neuronal activity exhibits scale-invariant properties indicative of criticality.
• To explore the role of gap junctions and environmental interactions in maintaining or altering this critical state.

Main Methods:

• Utilized light-sheet microscopy for high-resolution, whole-brain imaging in GCaMP transgenic zebrafish larvae.
• Recorded spontaneous neuronal activity to analyze spatio-temporal dynamics.
• Investigated the impact of gap junction blockers and sensory input/behavioral output on brain dynamics.

Main Results:

• Observed spontaneous activity propagating in 3D space, generating scale-invariant neuronal avalanches.
• Demonstrated statistical self-similarity in avalanche time courses and recurrence times across different scales.
• Found that gap junctions are crucial for maintaining criticality and that environmental interactions transiently shift the system to a more ordered state.

Conclusions:

• The zebrafish nervous system operates near a non-equilibrium phase transition, supporting a diverse range of neural activity modes.
• Criticality enables a broad repertoire of spatial, temporal, and interactive brain dynamics.
• Environmental interactions transiently reduce complexity, potentially optimizing sensory representation and motor control by moving away from criticality.