Hypnotic catalepsy-induced changes of regional cerebral glucose metabolism.

In an attempt to elucidate the physiological basis of hypnosis, we investigated the changes of whole-brain and regional cerebral glucose metabolism, from a state of resting wakefulness to a hypnotized state with whole-body catalepsy, using positron emission tomography and the 2[18F]fluorodeoxyglucose method in 15 highly hypnotizable adults. Neither the random order of study conditions nor any of the other experimental factors had a measurable effect, and there was no statistically significant global activation or metabolic depression. However, repeated measures analysis of variance revealed a statistically significant heterogeneity of symmetric regional responses: Mainly the occipital areas, including visual and paravisual cortex, became relatively deactivated, while some metabolic recruitment was found in structures involved in sensorimotor functions. The observed pattern of changes of regional cerebral activity corresponds with the shift of attention away from normal sensory input that hypnosis is known to produce.