Understanding the neurophysiological underpinnings of hypnosis with iEEG

GOMEZ-RAMIREZ J.; FREEDMAN S.; MATEOS D.; PEREZ VELAZQUEZ, J.L.; VALIANTE TAUFIK

Porto

Simposio; 10 th Bial Foundation Symposium; 2016

Bial Foundation

p { margin-bottom: 0.21cm; direction: ltr; color: rgb(0, 0, 0); }p.western { font-family: "Times New Roman",serif; font-size: 10pt; }p.cjk { font-family: "Times New Roman",serif; font-size: 10pt; }p.ctl { font-family: "Times New Roman",serif; font-size: 10pt; }he study of the neural correlates of hypnosisis still in its infancy, and arguably much of the same can be said ofcognition and consciousness. Research concerning the neuralunderpinnings of hypnosis, encounters substantial difficulties suchas the spatiotemporal limitations of EEG, PET and fMRI, the"ecological validity" of hypnosis sessions in thelaboratory, individual differences in susceptibility, and theunfitness of neuroimaging protocols to distinguish between theobservable brain effects of hypnotic induction and hypnoticsuggestion. Here,for the first time, the neurophysiological mechanisms of hypnosis areinvestigated using intracranial electroencephalography (iEEG). Thisrecording methodology removes the resolution problems associated withfunctional imaging. Patients with intractable epilepsy and implantedas part of their diagnostic exam were hypnotized. Baseline hypnosiswas measured following a standard induction procedure and before theadministration of motoric and cognitive suggestions. Patients withhigh and low hypnotizability were tested and compared. Phase basedsynchronization for connectivity analysis was calculated for threedifferent conditions: pre hypnotic state (eyes open and eyes closed),neutral hypnosis (eyes closed) and post hypnotic state (eyes open andeyes closed), across multiple frequency bands. We computed theintersite phase clustering difference between all the intracranialelectrodes across delta, theta, alpha, beta and gamma frequencies,for all conditions.Inhigh hypnotizable patients with bi-temporal burr holes, we find moreintersite synchronization, for theta and alpha bands, in the hypnoticcondition than in the eyes closed conditions, and a more modularorganization (more partitionable) in both the hypnotic and the eyesclosed conditions, compared to the eyes open conditions. Phasesynchronization distribution distance for all bands between hypnoticand post hypnotic states was shorter in high than in low hypnotizablepatients. Our preliminary results suggest that hypnosis represents agenuine brain state whose distinctiveness from states of deeprelaxation is in need of clarification. In future work, we will buildon this research to further explore the electrophysiology underlyingvolitional and nonvolitional actions, as well as the neuralcorrelates of subjective experience in response to hypnoticsuggestions.p { margin-bottom: 0.21cm; direction: ltr; color: rgb(0, 0, 0); }p.western { font-family: "Times New Roman",serif; font-size: 10pt; }p.cjk { font-family: "Times New Roman",serif; font-size: 10pt; }p.ctl { font-family: "Times New Roman",serif; font-size: 10pt; }