Landry, M.; da Silva Castanheira, J.; Sackur, J.; Raz, A.; Ogez, D.; Rainville, P.; Jerbi, K.

The ability for hypnotic responding is marked by great inter-individual variation in the population, while the neural underpinning of this variability remains elusive. The current work leveraged multivariate statistics and machine learning to probe the neural dynamics underlying inter-individual differences in hypnotic susceptibility. We assessed the efficacy of linear classifiers in distinguishing between high and low hypnotic susceptible individuals using neural features from resting-state electroencephalography (EEG) both pre- and post-hypnotic induction. Our focus encompassed both aperiodic and periodic components of the power spectrum, and graph theoretical measures derived from functional connectivity patterns. Several neural features from both pre- and post-induction significantly differentiated susceptibility levels, which underscores the complex dynamics of hypnotic phenomena. Based on model comparisons and feature ranking, we discerned the pre-induction aperiodic exponent as the primary discriminating neural feature, while periodic activity did not differ between groups. This novel finding not only resonates with the increasing emphasis on this neural component in broader EEG research but also promotes the idea that the primary neural distinction in hypnotic susceptibility is evident at baseline, even before hypnosis. Based on prevailing interpretation of aperiodicity in the EEG signal, our findings support the idea that hypnotic susceptibility might be an inherent trait reflected in the balance of cortical excitation and inhibition.