A deep-learning-based explainable consciousness indicator (ECI) uses EEG responses to transcranial magnetic stimulation and resting-state EEG to separately quantify arousal and awareness. Tested during sleep (n=6), general anesthesia (n=16), and severe brain injury (n=34), ECI distinguishes states such as ketamine-induced anesthesia and rapid eye movement sleep, which combine low arousal with high awareness. Parietal brain regions are most relevant for these measurements. The indicator offers a way to disentangle the two components of consciousness across physiological, pharmacological, and pathological conditions.
A world champion free diver's brain activity and connectivity shift markedly during a 6.5-minute breath-hold. EEG shows increased alpha wave power and connectivity, with decreased delta band connectivity. fMRI reveals heightened connectivity within the default mode network and visual areas, but reduced connectivity in sensorimotor cortices. These changes overlap with some meditation-related brain signatures but also include unique features suggesting altered somatosensory integration. Self-reports indicate that elite free divers may achieve a state of sensory dissociation during prolonged apnea, reflecting their ability to adapt psychologically and physiologically to extreme breath-holding.
Auto-induced cognitive trance (AICT) produces richer and more distinct subjective experiences than ordinary rest, auditory stimulation, or imagination. In 27 trained participants, free recalls of experiences were longer during AICT than in other conditions. Text mining identified four distinct classes of discourse, with AICT forming its own class clearly separate from ordinary conscious states. Nine content categories emerged, including nature, animals, body modifications, and difficulty describing thoughts. AICT was specifically characterized by reports of nature, animals, body modifications, and difficulty describing thoughts. These findings indicate that AICT generates a unique and richer phenomenology compared to other conscious states.