Brain activity during quiet wakefulness exhibits scale-free patterns of coordinated neuronal firing, thought to reflect a universal operating mechanism. This study examined how three common anesthetics—isoflurane, pentobarbital, and ketamine—at multiple doses alter these patterns in the mouse cortex using calcium imaging. Low doses largely preserved scale-free statistics, but surgical-plane anesthesia disrupted critical avalanche dynamics, producing multiple abnormal modes. The findings reveal distinct pathways away from the default critical state, depending on the anesthetic and individual responses, suggesting a complex relationship between criticality and consciousness.
The brain may maintain optimal information transmission even when its functional connectivity is drastically altered. The psychedelic compound ibogaine, which induces an altered state of consciousness, fundamentally changes functional connectivity in the retrosplenial cortex of mice. Despite these changes, the scale-free statistics of movement and of neuronal avalanches among behaviorally related neurons remain largely unaltered. This suggests that the propagation of information within biological neural networks is robust to changes in the functional organization of neuronal subpopulations, offering a new perspective on how adaptive functional networks may support optimal information transmission.