Segregated brain state during hypnosis

Jarno Tuominen; Sakari Kallio; Valtteri Kaasinen; Henry Railo

doi:10.1093/nc/niab002

Segregated brain state during hypnosis

Neurosci Conscious. 2021 Mar 10;2021(1):niab002. doi: 10.1093/nc/niab002. eCollection 2021.

Authors

Jarno Tuominen^{1

2}, Sakari Kallio^{1

3}, Valtteri Kaasinen^{2

4

5}, Henry Railo^{1

2

5

6}

Affiliations

¹ Department of Psychology and Speech-Language Pathology, Assistentinkatu 7, 20014 University of Turku, Turku, Finland.
² Turku Brain and Mind Center, 20014 University of Turku, Turku, Finland.
³ School of Biosciences, Högskolevägen 3, 54128 University of Skövde, Skövde, Sweden.
⁴ Division of Clinical Neurosciences, 20014 University of Turku, Turku, Finland.
⁵ Turku University Hospital, Kiinamyllynkatu 4-8, 20521 Turku, Finland.
⁶ Department of Clinical Neurophysiology, University of Turku, P.O. Box 52, 20521 Turku, Finland.

Abstract

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.

Keywords: brain dynamics; hypnosis; metastability; transcranial magnetic stimulation.