Decoding hypnotic consciousness: neural and experiential insights into induced and ideomotor suggestions

Summary

Hypnosis actively reorganizes brain networks rather than being a passive, low-arousal state. Using EEG and behavioral monitoring, the study found that light hypnosis suppressed parieto-occipital alpha and increased theta activity, while deeper hypnosis increased frontoparietal theta connectivity and reduced parasympathetic activation. During an ideomotor task, participants showed distinct behavioral patterns—tremblers and non-tremblers—despite similar disruptions in sense of agency. Tremblers attempted to move while feeling constrained; non-tremblers felt unable to initiate movement. EEG in tremblers showed increased frontoparietal gamma and reduced delta connectivity, indicating heightened sensorimotor integration and executive monitoring.

Study at a glance

Abstract

Hypnotic induction and ideomotor suggestions provide a powerful framework for investigating the remarkable capacity of verbal influence to reshape conscious experience, cognition, and motor control. We employed a multimodal approach combining high-density EEG, respiratory and behavioral monitoring, and first-person reports across three conditions: baseline resting state, progressive hypnotic induction (Light and Deep states), and an ideomotor task comparing a hypnotically suggested arm catalepsy to a voluntary simulation. EEG results revealed that light hypnosis was associated with early parieto-occipital alpha suppression and increased theta-band activity. As hypnosis deepened, frontoparietal connectivity increased in the theta while parasympathetic activation declined, challenging the view of hypnosis as a passive, low-arousal state and instead pointing to active top-down reorganization of large-scale brain networks. During the ideomotor state, participants exhibited distinct patterns of behavioral responsiveness, classified as tremblers and non-tremblers, despite reporting comparable disruptions in the sense of agency. Phenomenological analyses corroborated these distinctions, revealing that Tremblers attempted to move despite experiencing the action as involuntary or constrained, whereas Non-Tremblers refrained from acting due to a perceived impossibility or an inability to initiate the motor command. EEG connectivity analysis in Tremblers showed an increased frontoparietal gamma activity and reduced delta connectivity, suggesting heightened sensorimotor integration and greater executive monitoring under motor conflict. Together, these findings demonstrate that hypnosis engages dynamic top-down processes that reconfigure both neural connectivity and subjective experience depending on suggestion-types. They support predictive coding accounts of agency disruption and underscore the value of neurophenomenological methods for advancing consciousness science and informing clinical applications.