Existence of multiple transitions of the critical state due to anesthetics.

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.

Study at a glance

Abstract

Scale-free statistics of coordinated neuronal activity, suggesting a universal operating mechanism across spatio-temporal scales, have been proposed as a necessary condition of healthy resting-state brain activity. Recent studies have focused on anesthetic agents to induce distinct neural states in which consciousness is altered to understand the importance of critical dynamics. However, variation in experimental techniques, species, and anesthetics, have made comparisons across studies difficult. Here we conduct a survey of several common anesthetics (isoflurane, pentobarbital, ketamine) at multiple dosages, using calcium wide-field optical imaging of the mouse cortex. We show that while low-dose anesthesia largely preserves scale-free statistics, surgical plane anesthesia induces multiple dynamical modes, most of which do not maintain critical avalanche dynamics. Our findings indicate multiple pathways away from default critical dynamics associated with quiet wakefulness, not only reflecting differences between these common anesthetics but also showing significant variations in individual responses. This is suggestive of a non-trivial relationship between criticality and the underlying state of the subject.