Cerebral cortex (New York, N.Y. : 1991)
June 30, 2020
Andrés Canales-Johnson, Alexander J Billig, Francisco Olivares et al.
51 citations
During auditory bistable perception, a sequence of tones can be heard either as a single stream (integrated percept) or as two parallel streams (differentiated percept). Neural recordings showed that when perceptual alternations arose spontaneously, the integrated percept corresponded to increased neural information integration and decreased neural information differentiation across frontoparietal regions, while the differentiated percept showed the opposite pattern. When perception was driven by an external change in the sound stream, neural oscillatory power distinguished between percepts but information measures did not. The findings demonstrate that integration and differentiation of conscious perception map onto theoretically motivated neural information signatures, suggesting a direct link between phenomenology and neurophysiology.
Cerebral cortex (New York, N.Y. : 1991)
August 1, 2024
Evan Lewis-Healey, Enzo Tagliazucchi, Andrés Canales-Johnson et al.
27 citations
Intentional breathing techniques (breathwork) can induce altered states of consciousness similar to those produced by psychedelics. By tracking subjective experiences moment-by-moment alongside portable EEG recordings across 301 sessions from 14 novice participants, researchers found that psychedelic-like experiences—especially intense bliss—corresponded with increased neural complexity (Lempel-Ziv complexity) and changes in the aperiodic exponent of brain activity, but not with alpha brainwave power. These non-linear neural features map onto both broad positive experiences and specific psychedelic-like states, suggesting breathwork alters consciousness through mechanisms distinct from simple relaxation or meditation.
bioRxiv Preprint Server
March 4, 2022
Barbara Jachs, Manuel Camino Garcia, Andrés Canales-Johnson et al.
21 citations
preprint
A new method called Temporal Experience Tracing captures aspects of conscious experience continuously over time, allowing computational reconstruction of common experience states. Analyzing 852 meditations from 20 novice and 12 experienced meditators practicing Breathing, Loving-Kindness, and Open-Monitoring meditation, four recurring experience states were identified, averaging 6 minutes 46 seconds each. Three states matched the three meditation styles, and a fourth represented a low-motivational off-task state. Both groups spent more time in the task-related state during Loving-Kindness meditation and were less likely to transition to the off-task state compared to Breathing meditation. The method transforms the time dimension of subjective experience from narrative to measurable.
The European journal of neuroscience
March 1, 2022
Claudia Pascovich, Santiago Castro-Zaballa, Pedro A M Mediano et al.
16 citations
Neural complexity, measured by the Lempel-Ziv (LZ) compression algorithm, is lowest during NREM sleep and similar during REM sleep and wakefulness in cats with intracranial electrodes. Under subanaesthetic doses of ketamine (5, 10, and 15 mg/kg), complexity follows an inverted U-shaped curve in some electrodes, primarily in prefrontal cortex, rising at low doses and falling as doses approach anaesthetic levels. The variability in the ketamine dose-response curve across cats and cortices was larger than across sleep stages, highlighting differential local dynamics. These results replicate findings in humans and other species, showing neural complexity is sensitive to changes in conscious state.
Journal of cognitive neuroscience
May 14, 2025
Ruby M Potash, Sean D van Mil, Mar Estarellas et al.
7 citations
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.
bioRxiv Preprint Server
June 25, 2021
Claudia Pascovich, Santiago Castro-Zaballa, Pedro A.M. Mediano et al.
7 citations
preprint
Neural complexity, measured by the Lempel-Ziv compression algorithm, is lowest during NREM sleep and similar during REM sleep and wakefulness in cats with intracranial electrodes. Under subanesthetic doses of ketamine (5, 10, and 15 mg/kg), complexity follows an inverted U-shaped curve in some electrodes, especially in prefrontal cortex, rising at low doses and falling as doses approach anesthetic levels. Variability in the ketamine dose-response across cats and cortices is larger than sleep-stage differences, revealing distinct local dynamics. These results replicate findings in humans and other species, showing neural complexity is sensitive to conscious state changes and dose-dependent ketamine effects.
bioRxiv (Cold Spring Harbor Laboratory)
Ruby M. Potash, Sean D. Van Mil, Mar Estarellas et al.
4 citations
preprint
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.
Journal of cognitive neuroscience
May 27, 2026
Alejandro Chandia-Jorquera, Sean D van Mil, Mar Estarellas et al.
3 citations
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.
PsyArXiv
April 23, 2021
Renzo Carlo Lanfranco, Andrés Canales-Johnson, Boris Lucero et al.
2 citations
preprint
Consciousness research faces the challenge of combining subjective experience with objective neural data. Francisco Varela pioneered empirical approaches that bridge these sources. His neurophenomenological framework integrates first-person reports with neural measures, and his team discovered gamma-band phase synchronization as a neural marker of perceptual awareness. Varela also contributed to the study of time consciousness by combining subjective reports with neural measures. This review outlines key conceptual distinctions and philosophical challenges in consciousness research, highlighting Varela's non-reductive, comprehensive methodology.
bioRxiv
September 29, 2025
Alejandro Chandia-Jorquera, Sean D. Van Mil, Mar Estarellas et al.
preprint
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.
Frontiers in psychology
January 1, 2015
Francisco A Olivares, Esteban Vargas, Claudio Fuentes et al.
Neurophenomenology aims to bridge qualitative and quantitative methods in consciousness research through reciprocal constraints between first-person accounts and neurophysiological data, but has faced methodological difficulties in systematically obtaining and analyzing subjective reports. Recently developed second-person methods—interview techniques that elicit verbal and non-verbal information—offer a way to obtain detailed subjective reports. This paper examines the potential of second-person methodologies for neurophenomenology, describes available interview techniques, analyzes two experimental studies that incorporate them, and identifies the validation problem of comparing results across participants and interviewers. The authors argue that second-person methods are a powerful approach for closing the gap between experiential and neurobiological levels of description.
Frontiers in psychology
January 1, 2015
Valdas Noreika, Andrés Canales-Johnson, Justin Koh et al.
During the transition from relaxation to drowsiness, people often experience hypnagogic phenomena such as perceptual imagery or linguistic intrusions—sudden, unpredictable anomalies in inner speech. In a single participant across 10 EEG sessions, drowsiness depth (measured by Hori stages) increased in the 20 seconds before reporting such an experience, and EEG Dimension of Activation values decreased, indicating rapid changes in brain predictability. Linguistic intrusions were associated with higher alpha and gamma power over the left hemisphere, while perceptual imagery corresponded to higher beta power over the right hemisphere. These results suggest that the modality and incongruence of hypnagogic experiences have distinct EEG signatures, and sleep onset offers a way to study the neural basis of consciousness fragmentation in healthy individuals.