During an advanced concentrative absorption meditation called jhana, characterized by highly stable attention and mental absorption, the brain's nonoscillatory dynamics—captured by nonlinear connectivity metrics—distinguish the meditative state better than oscillatory synchrony. Combining attention-related phenomenological ratings with these nonlinear metrics improves the detection of the meditative state compared to using neural data alone. Deeper absorption states show an equalization of feedback and feedforward processes, suggesting a balance between internally and externally driven information processing. The findings, based on EEG recordings from a single meditator with over 20,000 hours of practice across 29 sessions, offer initial insights into the distinct neural dynamics of refined conscious states.
Pure awareness, a state of minimal phenomenal experience, can be reliably studied through transcendental meditation. In 33 experienced TM practitioners compared to controls doing mental counting, TM produced significantly greater intensity and temporal variability of pure awareness, unrelated to years of practice. Using EEG and multivariate classification, a double dissociation emerged: temporal entropy and aperiodic dynamics best distinguished TM from counting, while low-frequency functional connectivity best distinguished TM from its own baseline. These differences reflected distributed neural patterns, not localized effects. TM showed little carryover into rest, unlike counting. The findings characterize pure awareness electrophysiologically and support neurophenomenology as a framework for studying minimal experience.