Hypnosis reduces activity in the default mode network (DMN), a set of brain regions active during rest and linked to self-awareness and task-independent thinking, while increasing activity in prefrontal attentional systems. Using brain imaging and subjective measures during passive visual stimulation, the authors found that the state of attentional absorption after a hypnotic induction was associated with these neural changes. Hypnosis and spontaneous conceptual thought at rest were both subjectively and neurally distinct, offering insight into the hypnotic state and its neural basis.
Involuntary movements in neuropsychiatric disorders and culturally influenced dissociative states, such as delusions of alien control and spirit possession, involve distinct brain processes. Using fMRI in 15 highly hypnotically susceptible volunteers, suggestions modelled different experiences of loss of self-control: external personal control (like delusions of control), internal personal control (like spirit possession), and impersonal control by a machine (technical delusions). Brain activity and connectivity varied across these conditions.
Voluntary control and awareness of movement are central to selfhood and responsibility, yet can be lost in neuropsychiatric syndromes and dissociative states like spirit possession. Using suggestion and fMRI in 15 highly hypnotically suggestible subjects, loss of perceived control of movements was linked to reduced connectivity between the supplementary motor area (SMA) and motor regions. Reduced awareness of involuntary movements corresponded with less activation in parietal cortices and insula. These results suggest the sense of voluntary control may critically depend on SMA coupling with motor systems, offering a neural basis for narrowed awareness in pathological and culturally influenced dissociative phenomena.