Hypnosis-induced modulation of corticospinal excitability during motor imagery

Paola Cesari,Mehran Emadi Andani,Michele Modenese,Sara Benedetti,Mirta Fiorio

doi:10.1038/s41598-020-74020-0

Abstract

Hypnosis can be considered an altered state of consciousness in which individuals produce movements under suggestion without apparent voluntary control. Despite its application in contexts implying motor control, evidence for the neurophysiological mechanisms underlying hypnosis is scarce. Inter-individual differences in hypnotic susceptibility suggest that sensorimotor strategies may manifest in a hypnotic state. We tested by means of transcranial magnetic stimulation applied over the primary motor cortex whether motor system activation during a motor imagery task differs in the awake and in the hypnotic state. To capture individual differences, 30 healthy volunteers were classified as high or low hypnotizable (Highs and Lows) according to ad-hoc validated scales measuring hypnotic susceptibility and personality questionnaires. Corticospinal activation during motor imagery in the hypnotic state was greater in the Highs than the Lows. Intrinsic motivation in task performance and level of persuasion modulated corticospinal activation in the Highs. Corticospinal system activation under hypnosis may have practical implications that merit research in areas where hypnosis can be applied to improve motor performance, such as loss of motor abilities and sports.

Highlights

Hypnosis can be considered an altered state of consciousness in which individuals produce movements under suggestion without apparent voluntary control
Post-hoc comparisons showed that both muscles were significantly more active during motor imagery compared to rest and that the first dorsal interosseous (FDI) was more active than the abductor digiti minimi (ADM) at both motor imagery and rest (Fig. 2)
The present findings provide evidence for the idea that imagining a movement in the hypnotic state modulates corticospinal system excitability depending on an individual’s sensitivity to hypnosis

Summary

Introduction

Hypnosis can be considered an altered state of consciousness in which individuals produce movements under suggestion without apparent voluntary control. Corticospinal activation during motor imagery in the hypnotic state was greater in the Highs than the Lows. Haggard et al.[6] found that under hypnosis the mechanism of action control was not altered nor was the conscious experience of the action or the ability to make temporal judgments about actions. They found that individuals planed their actions in a similar way irrespective of whether under hypnosis or in the awake state. A professional hypnotizer (M.M.) categorized a preselected sample of 30 healthy volunteers by their level of sensitivity to hypnosis based on Stanford Hypnotic

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Results

Conclusion