Modulation of the heartbeat evoked cortical potential by hypnotizability
and hypnosis.
Abstract
Hypnotizability is a psychophysiological trait measured by scales and
associated with several differences including interoceptive accuracy and
the morpho-functional characteristics of interoception-related brain
regions. The aim of the study was to assess whether the amplitude of the
heartbeat evoked cortical potential (HEP), a correlate of interoceptive
accuracy, differs in participants with low (lows) and high (highs)
hypnotizability scores (assessed by the Stanford Hypnotic Susceptibility
Scale, form A) before and after the induction of hypnosis. ECG and EEG
were monitored in 16 highs and 15 lows during an experimental session
including open eyes baseline (B), closed eyes relaxation (R), hypnotic
induction (IND), neutral hypnosis (NH), post session baseline (Post). No
significant difference was observed between groups and conditions in
autonomic variables. The HEP amplitude was lower in highs than in lows
at the right parietal site, likely due to hypnotizability-related
differences in the functional connection between the right insula and
parietal cortex. It increased in highs and decreased in lows across the
session, possibly due to the highs’ preeminently internally directed
attention and to the lows’ possible disengagement from the task. Since
interoception is involved in several cognitive-emotional functions, its
hypnotizability-related differences may contribute to the variability of
experience and behavior in daily life.