473 Cognitive, visual, auditive and pain-related characteristics of the REM dreams

Abstract

EEG was recorded monopolarly at frontal (F3, F4), central (C3, C4) and posterior (in the middle of O1-P3T5 and O2-P4-T6 triangles) derivations during the hypnotic induction of the Stanford Hypnotic Clinical Scale (SHCS) and during performance following suggestions of hypnotic dream and age-regression as expressed in the before-mentioned scale. 10 low-hypnotizable and 9 highly-hypnotizable and right-handed female students participated in one experimental session. Evaluations were Fast-Fourier spectral analyses during the following conditions: walking-rest in eyes-open and eyes-closed condition; early middle, and late phases of hypnotic induction; rest-hypnosis in eyes closed condition; hypnotic dream and age regression. After spectral analysis of 0 to 44 Hz, the mean spectral amplitude estimates across seven Hz bands (theta1, 4–6 Hz, theta2, 6–8 Hz; alpha1, 8–10 Hz; alpha2, 10–13 Hz; beta1, 13–16 Hz; beta2, 16–20 Hz; beta3, 20–36 Hz) and the 40-Hz EEG band (36–44 Hz) for each experimental condition were extracted. In eyes-open and -closed conditions on walking and hypnosis highly-hypnotizable subjects produced a greater 40-Hz EEG amplitude than did low hypnotizable subjects at all frontal, central and posterior locations. In the early and middle hypnotic induction highly-hypnotizables displayed a greater amount of beta3 than did low hypnotizables and this difference was even more pronounced in the left hemisphere. With posterior scalp recordings, during hypnotic dream and age regression, high hypnotizables displayed, as compared with the rest-hypnosis condition, a decrease in alpha1 and alpha2 amplitudes. This effect was absent for low hypnotizables. Beta1, beta2 abd beta3 amplitudes increased in the left hemisphere during age regression for high hypnotizables; low hypnotizables, in contrast, displayed hemispheric balance across imaginative tasks. High hypnotizables during the hypnotic dream are also displayed in the right hemisphere a greater 40-Hz EEG amplitude as compared with the left hemisphere. This difference was even more evident for posterior recording sites. This hemispheric trend was not evidenced for low hypnotizable subjects. Theta power was never a predictor of hypnotic susceptibility, 40-Hz EEG amplitude displayed a very high main effect (p < 0.004) for hypnotizability in hypnotic conditions by displaying a greater 40 Hz EEG amplitude in high hypnotizables with respect to lows.