Nature Communications
February 25, 2022
Minji Lee, Leandro Sanz, Alice Barra et al.
120 citations
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.
Communications Biology
June 29, 2022
Anira Escrichs, Yonatan Sanz Perl, Carme Uribe et al.
67 citations
Different brain states—resting, meditating, deep sleep, and disorders of consciousness after coma—are underpinned by distinct spatiotemporal dynamics that can be characterized using turbulence theory. Non-conscious states tend to be more synchronous, while conscious states are more asynchronous, but the work goes beyond this simple dichotomy. A model-free analysis of human neuroimaging data applied Kuramoto's turbulence framework with coupled oscillators and measured information cascades across spatial scales. A complementary model-based approach used exhaustive computer simulations of whole-brain models fitted to those measures to study information encoding. The framework shows that turbulence theory provides excellent tools for describing and differentiating between brain states.
NeuroImage
February 9, 2021
Riku Ihalainen, Olivia Gosseries, Frederik van de Steen et al.
30 citations
Using dynamic causal modelling of high-density EEG recordings from 10 people during propofol anaesthesia, the study evaluated how three resting state networks—the default mode network, the salience network, and the central executive network—contribute to consciousness. Loss of consciousness reduced inter-network connectivity in the parietal cortex, especially feed-forward frontoparietal and parietal connections at the precuneus node within the default mode network. Within the salience and central executive networks, unconsciousness generated small increases in bidirectional connectivity. The most consistent predictions of consciousness came from a key set of frontoparietal connections, supporting the importance of the posterior hot zone in explaining loss of consciousness.
NeuroImage
June 1, 2024
Pradeep Kumar G, Rajanikant Panda, Kanishka Sharma et al.
20 citations
High-order interactions between brain regions, measured as synergistic and redundant information, change differently across three non-ordinary states of consciousness. During Rajyoga meditation, synergy increased across the whole brain in delta and theta brainwave bands, while redundancy decreased in frontal, central, and posterior electrodes in delta and beta bands. During hypnosis, synergy decreased in mid-frontal, temporal, and mid-centro-parietal electrodes in the delta band, and in left frontal and right parietal electrodes in the beta2 band. During auto-induced cognitive trance, synergy decreased in delta and theta bands in left-frontal, right-frontocentral, and posterior electrodes, and at the whole brain level in the alpha band. Redundancy changes during hypnosis and auto-induced cognitive trance were not significant. Subjective reports of absorption, dissociation, and mystical experience did not correlate with the high-order measures.
Journal of Cognitive Neuroscience
January 1, 2023
Rajanikant Panda, Audrey Vanhaudenhuyse, Andrea Piarulli et al.
15 citations
During hypnosis, brain connectivity changes in ways that suggest more efficient cognitive processing and less mind-wandering. In nine healthy participants, hypnosis increased delta-wave connections between frontal brain regions and between frontal and parietal regions. It decreased alpha and beta-2 connections among frontal, parietal, and midline areas. Network analysis showed greater segregation of short-range connections in delta and alpha bands and greater integration of long-range connections in beta-2 bands. Frontal and right parietal electrodes became central hubs. These altered dynamics may reflect a modified balance between internal and external awareness networks.
Brain Structure and Function
January 1, 2021
Jitka Annen, Rajanikant Panda, Charlotte Martial et al.
15 citations
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.
The International journal of clinical and experimental hypnosis
January 1, 2024
Mélanie Louras, Audrey Vanhaudenhuyse, Rajanikant Panda et al.
8 citations
Combining virtual reality with mind-body therapies such as meditation, mindfulness, relaxation, and hypnosis can reduce pain in both healthy volunteers and patients. A scoping review of 43 studies found that the combination is feasible, well-tolerated, and potentially useful for decreasing pain, and also improves anxiety, mood, and relaxation. However, insufficient research and a lack of multidimensional studies limit full understanding of their potential. More randomized controlled trials with usability evaluations are needed to incorporate these approaches into routine clinical practice.
Frontiers in Neuroscience
February 13, 2024
Benedetta Cecconi, Javier Montupil, Sepehr Mortaheb et al.
6 citations
Disconnected consciousness, where subjective experience persists but is cut off from the external world, often occurs during sleep or sedation but is difficult to study because unresponsive people may still be conscious and amnesia can erase memories of events. This research uses a serial awakening paradigm during mild propofol sedation: participants hear sounds and are interviewed while still sedated to determine whether they are connected or disconnected from the environment, bypassing the need for behavioral responses and amnesia. Functional MRI data reveal neural activity patterns during these states, testing whether sensory disconnection arises at the thalamus or from disrupted information flow to higher brain regions. Slow-wave activity's role is also explored via high-frequency BOLD oscillations. Findings could improve anesthesia monitoring and assessment of patients with reduced consciousness.
Frontiers in Neuroscience
January 1, 2018
Rajanikant Panda, Olivia Gosseries, Audrey Vanhaudenhuyse et al.
2 citations
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Front Psychol
June 4, 2026
Raghuwansh Singh, Rajanikant Panda, Mika P. Tarvainen et al.
Meditation in trained Rajyoga practitioners produces a consistent physiological signature: heart rate variability (HRV) increases, respiration slows, and the coupling between breathing and heart rate strengthens, indicating greater parasympathetic nervous system engagement. The study measured 55 practitioners across three 10-minute states—before, during, and after meditation—using multiscale HRV metrics. Time-domain and frequency-domain HRV indices rose during meditation and partially recovered afterward, while non-linear measures also shifted significantly. Exploratory sex-stratified analyses suggested possible differences in effect magnitude that require further study. The findings support multiscale cardiorespiratory analysis as an operational marker of altered consciousness during Rajyoga meditation.
bioRxiv Preprint Server
September 28, 2022
Yonatan Sanz Perl, Carla Pallavicini, Juan Piccinini et al.
preprint
Brain states are often described on a single scale from full consciousness to unconsciousness, but this ignores the complex, high-dimensional nature of brain activity. By combining whole-brain modeling, data augmentation, and deep learning, researchers mapped states of consciousness into a low-dimensional space where distances reflect similarities between states. They found an orderly trajectory from wakefulness to brain-injured patients, with coordinates related to functional modularity and structure-function coupling, both increasing as consciousness is lost. Model perturbations provided a geometric interpretation of state stability and reversibility. The work suggests conscious awareness depends on functional patterns encoded as a low-dimensional trajectory within the vast space of brain configurations.
bioRxiv Preprint Server
July 2, 2020
Yonatan Sanz Perl, Carla Pallavicini, Ignacio Pérez Ipiña et al.
preprint
The level of consciousness—how conscious someone is—is often measured by how similar their brain activity is to normal wakefulness. However, this approach misses important information about how stable that state is. Using computer models of the whole brain, the authors show that the stability of a conscious state—how easily it can be disrupted—provides additional, complementary information. They propose a new framework that sorts brain states by both their similarity to wakefulness and their stability, which helps distinguish between different types of unconsciousness: natural sleep, anesthesia, and brain injury. This framework offers a more complete way to characterize and differentiate states of consciousness.