Segregated brain state during hypnosis

Can the brain be shifted into a different state using a simple social cue, as tests on highly hypnotizable subjects would suggest? Demonstrating an altered global brain state is difficult. Brain activation varies greatly during wakefulness and can be voluntarily influenced. We measured the complexity of electrophysiological response to transcranial magnetic stimulation in one 'hypnotic virtuoso'. Such a measure produces a response arguably outside the subject's voluntary control and has been proven adequate for discriminating conscious from unconscious brain states. We show that a single-word hypnotic induction robustly shifted global neural connectivity into a state where activity remained sustained but failed to ignite strong, coherent activity in frontoparietal cortices. Changes in perturbational complexity indicate a similar move towards a more segregated state. We interpret these findings to suggest a shift in the underlying state of the brain, likely moderating subsequent hypnotic responding.CC BY 4.0Correspondence address: Department of Psychology, Publicum/Assistentinkatu 7, University of Turku, Turku 20014, Finland; Phone: +358 50 302 3719, Fax: +358 29 450 5040 E-mail: jarno.tuominen@utu.fiThis work was supported by the Academy of Finland (grant number 308533) to H.R., and by the Signe and Ane Gyllenberg Foundation to S.K.Academy of Finland European Commission 308533