During a deep meditative state called jhana, the brain's non-oscillatory, nonlinear neural activity—rather than oscillatory synchrony—best distinguishes the state from ordinary waking consciousness. In a single highly experienced meditator (over 20,000 hours of practice) studied across 29 sessions, EEG recordings showed that combining subjective ratings of attention with a nonlinear connectivity metric improved the ability to decode the meditative state compared to using neural measures alone. Deeper jhana states were marked by a balance between feedback and feedforward neural processes, indicating an equalization of internally and externally directed information processing. These findings suggest that refined conscious states involve distinct large-scale neural dynamics not captured by traditional oscillatory measures.
A neurophenomenological study using EEG and experience tracing in 33 experienced Transcendental Meditation (TM) practitioners and matched controls (doing mental counting) found that TM reliably elicits reports of pure awareness—a minimal form of experience with little mental content. TM practitioners reported greater intensity and more variable timing of pure awareness, independent of years of practice. Distinct neural signatures separated TM from counting: temporal entropy and aperiodic brain activity best distinguished the two states, while phase-based connectivity was least informative. Comparing TM to its own baseline, low-frequency connectivity dominated and temporal entropy mattered little. These patterns were distributed across the brain, not localized. Counting, but not TM, showed lingering effects after the task. The results characterize pure awareness electrophysiologically and support neurophenomenology as a way to study minimal experience.