Neural Correlates of a Trance Process and Alternative States of Consciousness in a Traditional Healer

Abstract

Trance processes are a form of altered states of consciousness (ASC) widely reported across cultures. Entering these states is often linked to auditory stimuli such as singing, chanting, or rhythmic drumming. While scientific research into this phenomenon is relatively nascent, there is emerging interest in investigating the neural correlates of altered states of consciousness such as trance. This report aims to add to this field of ASC through exploring how the perception of an experienced Sangoma (traditional South African healer) entering a trance process correlates to blood-oxygen-level-dependent (BOLD) signal modulation with auditory stimuli. Functional Magnetic Resonance Imaging (fMRI) data were analyzed using a General Linear Model comparing music versus no music condition multiplied by the percept of experiencing trance (High or Low). Positive BOLD activation was shown in the auditory cortex in both hemispheres during a trance process. Other brain regions tightly correlated to trance perception were the right parietal, right frontal, and area prostriata (p < 0.05, Bonferroni corrected). The orbitofrontal cortex (part of the Default Mode Network) was negatively activated and most correlated with music when trance was high, showing the largest differential between high and low trance perception. This is the first study to directly correlate BOLD signal variations in an expert subject’s percept of trance onset and intensity, providing insight into the neural signature and dynamics of this unique form of ASC. Future studies should examine in greater detail the perception of trance processes in expert subjects, adding other neuroimaging modalities to further investigate how these brain regions are modulated by trance expertise.

Consciousness as an intelligent complex adaptive system: A neuroanthropological perspective

“…Moment‐by‐moment consciousness, as we have seen, is mediated by the highest level of functional cluster. Alternative states of consciousness, like meditation and trance states, occur due to transformations in brain states (Ott et al, 2011; Rogerson et al, 2021). Consciousness as a whole may undergo dramatic transformations over time.…”

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).…”

Transcendental medication: The evolution of mind, culture, and healing. ChrisLynn, Routledge, 2022. 130 pp

“…As such, the book might have taken up existing neurophysiological results in greater detail. While the use of fMRI to investigate dissociative cultural practice is not available to the field anthropologist, there are now a handful of laboratory studies that have used fMRI to study trance (Hove et al, 2016; Rogerson et al, 2021). Their results can be used to interpret the impact of cortisol or blood pressure on neurological processes more directly associated with the subjective experience and cultural framing of dissociative states.…”