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.
Keywords: interoception, heartbeat, HEP, hypnosis, hypnotizability.