EEG source localization and global dimensional complexity in high- and low-hypnotizable subjects: A pilot study

Individuals differ in hypnotizability. Information on hypnotizability-relat ed EEG characteristics is controversial and incomplete, particularly on int racerebral source localization and EEG dimensionality. 19-channel, eyes-clo sed resting EEGs from right-handed, healthy, 8 high- and 4 low-hynotizable subjects (age: 26.7 +/- 7.3 years) were analyzed. Hypnotizability was rated after the subjects' ability to attain a deep hypnotic stage (amnesia). FFT Dipole Approximation analysis in seven EEG frequency bands showed signific ant differences (p < 0.04) of source gravity center locations for theta (6. 5-8 Hz, more posterior and more left for highs), beta-1 and beta-2 frequenc ies (12.5-18 and 18.5-21 Hz; both more posterior and more right for highs). Low Resolution Electromagnetic Tomography (LORETA) specified the cortical anteriorization of beta-1 and beta-2 in low hypnotizables. Power spectral a nalysis of Global Field Power time series (curves) showed no overall power differences in any band. Full-band Global Dimensional Complexity was higher in high-hypnotizable subjects (p < 0.02). Thus, before hypnosis, high and low hypnotizables were in different brain electric states, with more poster ior brain activity gravity centers (excitatory right, routine or relaxation left) and higher dimensional complexity (higher arousal) in high than low hypnotizables. Copyright (C) 2001 S. Karger AG, Basel.