A. Gemignani et al., Changes in autonomic and EEG patterns induced by hypnotic imagination of aversive stimuli in man, BRAIN RES B, 53(1), 2000, pp. 105-111
Autonomic and electroencephalographic (EEG) responses to aversive stimuli p
resented by means of hypnotic suggestion have been studied in man. Healthy
volunteers with simple phobia were screened for susceptibility to hypnosis.
The experimental paradigm included periods of rest during which the hypnot
ized subjects were asked to produce an emotionally neutral mental image and
periods of emotional activation in which they were asked to image a phobic
object. Heart rate (HR), respiratory frequency (RF) and EEG were processed
to obtain the HR-related indexes of sympatho-vagal balance and the EEG spe
ctral components. The results showed a significant increase in HR and RF wi
th a shift of the sympatho-vagal indexes towards a sympathetic predominance
during the hypnotic emotional activation. EEG activity showed a significan
t increase in the gamma band with a left fronto-central prevalence. There w
as also a less pronounced increase in the beta band. In conclusion, by mean
s of hypnosis, autonomic and behavioral responses to fear-like stimuli can
be induced in man in a reproducible and controlled manner. Such a paradigm
could be applied in human neuroimaging studies to identify central nervous
structures that modulate stress and fear-related reactions. (C) 2000 Elsevi
er Science Inc.