Dynamic neuronal ensembles encode burst-suppression revealed by cortex-wide optical-electrical interfaces

Burst suppression is widely observed across cortical regions during reversible or pathological unconsciousness, yet its neuronal organization remains incompletely understood. Here we present an integrated Cortex-wide Optical-electrical Dual-modal Explorer (CODE) system to examine neuronal dynamics during burst suppression under isoflurane anesthesia in the mouse. We identified distinct cortex-wide neuronal ensembles that alternately associate with burst or suppression events, exhibiting dynamic neuronal recruitment and reactivation during anesthesia. Burst events were marked by highly synchronized neuronal activity early in the burst phase with high functional connectivity, whereas suppression events displayed more asynchronous, temporally distributed activity with reduced connectivity. Transitions between these states involved sequential, directionally organized propagation across cortical regions. ECoG bursts propagated from bilateral sensory cortices to motor areas within tens of milliseconds with increasing synchrony with calcium activity. Furthermore, we established a robust metric linking ECoG and calcium signals, revealing state-dependent interpretability. These findings reveal the single-neuron-to-population architecture of burst suppression and illustrate how integrated optical-electrical measurements enable high-resolution, large-scale interrogation of cortical dynamics.