Non-invasive brain stimulation (NIBS) in the modulation of hypnotic experience and hypnotizability

Non-Invasive Brain Stimulation (NIBS) techniques, including Transcranial Magnetic Stimulation (TMS) and Transcranial Direct Current Stimulation (tDCS), have emerged as valuable tools in neuroscience, clinical interventions, and hypnosis research. NIBS enables the modulation of neural activity to explore brain-behaviour relationships through causal approaches. TMS, relying on magnetic fields to induce cortical stimulation, has demonstrated its utility in enhancing hypnotic suggestibility, albeit with limitations such as imprecise targeting of stimulated neuronal populations and variability in individual responses. These limitations, including imprecise targeting and inter-individual variability in responses, are also common to tDCS, which applies weak electrical currents to influence cortical excitability, offer more practical adaptability, making it a promising alternative for applications in hypnosis. In hypnosis research, NIBS studies have primarily targeted the dorsolateral prefrontal cortex (DLPFC), a region implicated in executive processes and hypnotic phenomena. Findings from TMS and tDCS studies suggest a modulatory role of the DLPFC in hypnotizability, with inhibitory stimulation enhancing hypnotic depth and responsiveness for some individuals. However, methodological challenges highlight the need for further exploration. Additionally, both TMS and tDCS suffer from further issues such as the challenge of ensuring effective blinding, the presence of placebo effects (which may interfere with the genuineness of observed effects), and high inter-subject variation even within the same study population. Despite these challenges, NIBS suggests clinical potential in augmenting hypnotic responsiveness, which could enhance pain management, emotional regulation, and broaden the applicability of hypnotherapy to resistant individuals. Further, these advancements promise to deepen our understanding of the neurophysiological basis of hypnosis, opening avenues for personalized and targeted neuromodulation strategies.