Neural Correlates of the Shamanic State of Consciousness

Abstract

Psychedelics have been recognized as model interventions for studying altered states of consciousness. However, few empirical studies of the shamanic state of consciousness, which is anecdotally similar to the psychedelic state, exist. We investigated the neural correlates of shamanic trance using high-density electroencephalography (EEG) in 24 shamanic practitioners and 24 healthy controls during rest, shamanic drumming, and classical music listening, followed by an assessment of altered states of consciousness. EEG data were used to assess changes in absolute power, connectivity, signal diversity, and criticality, which were correlated with assessment measures. We also compared assessment scores to those of individuals in a previous study under the influence of psychedelics. Shamanic practitioners were significantly different from controls in several domains of altered states of consciousness, with scores comparable to or exceeding that of healthy volunteers under the influence of psychedelics. Practitioners also displayed increased gamma power during drumming that positively correlated with elementary visual alterations. Furthermore, shamanic practitioners had decreased low alpha and increased low beta connectivity during drumming and classical music and decreased neural signal diversity in the gamma band during drumming that inversely correlated with insightfulness. Finally, criticality in practitioners was increased during drumming in the low and high beta and gamma bands, with increases in the low beta band correlating with complex imagery and elementary visual alterations. These findings suggest that psychedelic drug-induced and non-pharmacologic alterations in consciousness have overlapping phenomenal traits but are distinct states of consciousness, as reflected by the unique brain-related changes during shamanic trance compared to previous literature investigating the psychedelic state.

Hypnotic suggestions cognitively penetrate tactile perception through top-down modulation of semantic contents

“…This might serve an unlocking stimulus processing from frontal cortical areas thereby facilitating an interpretation of the stimuli different from their physical appearance. Our findings are in line with other studies exploring states evoked by hypnosis or placebo-conditions showing comparable changes in connectivity 29 , 30 or late SEP components 12 , although we did not find effects in paired-pulse behaviour 13 . However, our study differed in a number of methodological details.…”

Trance, posture, and tobacco in the Casas Grandes shamanic tradition: Altered states of consciousness and the interaction effects of behavioral variables

“…Trance can be either normative or pathological, and ranges on a continuum from an energetic sleeplike state to a catatonic state associated with memory issues. While in trance, neurological shifts often cause people to perceive an alternate reality detected by seeing, hearing, feeling, tasting, and smelling things that are not perceived by people in standard consciousness (Hove et al., 2015; Huels et al., 2021; Rogerson et al., 2021). Trance is commonly associated with religious experiences, especially in shamanic traditions in which shamans use trance to perceive otherwise hidden spirits and sometimes engage in soul flight that allows them to travel through this and other worlds (e.g., the spiritual Upper or Lower Worlds) (Bourguignon, 1989; Eliade, 1964; Halifax, 1982; Kohek et al., 2020; Vitebsky, 2001).…”

La transe cognitive auto-induite : caractéristiques et applications thérapeutiques potentielles

“…Par ailleurs, dans l'étude de Huels et al [31], les corrélats neuronaux de la transe chamanique ont également été investigués via des EEG. Une augmentation des ondes gamma ressort lors de la transe, positivement corrélée au degré d'altération visuelle rapportée par les « praticiens chamanes ».…”

“…Les résultats suggèrent que cet état de transe impacte l'image corporelle (« les limites entre moi et l'environnement se sont dissoutes ») et le sens du temps (« j'ai eu un sentiment d'intemporalité »). L'expérience de transe est décrite comme un état « altéré » (« j'ai eu une expérience que je décrirai comme religieuse, spirituelle, ou transcendante ») avec une absorption très forte (« je pouvais me concentrer et plonger complètement dans ce que je vivais ; je n'étais pas distrait par des événements extérieurs »).Dans leur étude récente, Huels et al se sont également intéressés à la transe[31], en analysant les caractéristiques phénoménologiques chez 24 « praticiens chamaniques » et 24 sujets contrôles. Il ressort de cette étude que la transe chamanique se caractérise par une imagerie complexe, des altérations visuelles, un sentiment d'unité et de bonheur, une impression de vivre une expérience spirituelle et d'être désincarné, et une impression de discernement plus grand.…”