Higher neuroentropy—the complexity or diversity of brain activity—characterizes wakefulness, REM sleep, and psychedelic states, while reduced entropy marks anesthesia, deep NREM sleep, and disorders of consciousness. Psychedelic substances pharmacologically increase entropy, corresponding to vivid, varied experience; unconscious states show low-complexity dynamics. Entropy measures have clinical value for anesthesia monitoring and detecting covert awareness. Challenges remain in metric selection, distinguishing meaningful complexity from noise, and mapping entropy to the content of consciousness. Overall, neuroentropy serves as a physiologically grounded index for level of consciousness and its alterations.
A theoretical model proposes that tubulin dimers in neuronal microtubules can achieve collective quantum coherence, leading to wavefunction collapses that manifest as avalanches within a self-organized criticality framework. Inspired by Orchestrated Objective Reduction (Orch-OR) theory, the model suggests that microtubule subunits become transiently entangled via dipole-dipole couplings, forming coherent domains that undergo sudden self-collapse. Using a network of tubulin-like nodes with scale-free connectivity, the system exhibits power-law avalanches near criticality, identified with quantum wavefunction collapse events. Estimated objective reduction times fall in the 10–200 ms range, consistent with Orch-OR conscious moment timescales, suggesting a bridge between sub-neuronal quantum processes and large-scale neural activity.