40-Hz EEG activity during hypnotic induction and hypnotic testing.
The present study evaluates changes in left and right 40-Hz EEG production for 19 high and 20 low hypnotizable female Ss during the hypnotic induction and the administration of the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) of the Weitzenhoffer and Hilgard (1962). Scalp recorded 40-Hz EEG density was obtained from the middle of the O1-P3-T5 and O2-P4-T6 triangles. As the hypnotic induction proceeded, high hypnotizable Ss exhibited a shift to greater right-hemisphere activity as compared to a waking-state rest condition. In contrast, low hypnotizable Ss, showed a reduction in left- and right-hemisphere activity. No differences between groups for SHSS:C ideomotor items were observed. A main effect for Hypnotizability among SHSS:C imaginative items was found. A Hypnotizability x Hemisphere x Trial interaction was found for both sensory distortion and imaginative SHSS:C items. A comparison was made between low versus high hypnotizable Ss of 40-Hz EEG activity while they passed the same item. The results of these comparisons indicate that differences in brain activity might be partially related to the differences between experiencing a hypnotic suggestion or failing to do so. Significant relationships between 40-Hz EEG production and hypnotizability and 40-Hz EEG production and level of amnesia were also found.
DePascalis
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Dipartimento di Psicologia, Universita di Roma, La Sapienza, Italia.
Penna
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PM
D000328:Adult; D000513:Alpha Rhythm; D001143:Arousal / Q000502:physiology; D001288:Attention / Q000502:physiology; D002540:Cerebral Cortex / Q000502:physiology; D004292:Dominance, Cerebral / Q000502:physiology; D004569:Electroencephalography; D006801:Humans; D006990:Hypnosis / Q000379:methods*; D008297:Male; D010556:Personality Tests