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.