The International Journal of Clinical and Experimental Hypnosis
In the last decade, functional brain imaging techniques ranging from fMRI to PET to EEG have added to understanding the mechanisms involved in cognitive, affective, and motoric processes. More recently, as demonstrated by papers in a variety of neuroscience journals, the hypnotic experience and its modulation of critical human processes such as pain have added hypnotic procedures to the experimental techniques available for the neuroscience community.
In a long-term longitudinal study of aging in rhesus monkeys, a primary objective has been to determine the effects of aging and caloric restriction (CR) on behavioral and neural parameters. Through the use of automated devices, locomotor activity can be monitored in the home cages of the monkeys. Studies completed thus far indicate a clear age-related decline in activity consistent with such observations in many other species, including humans. However, no consistent effects of CR on activity have been observed.
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.
Proceedings of the National Academy of Sciences of the United States of America
An auditory hallucination shares with imaginal hearing the property of being self-generated and with real hearing the experience of the stimulus being an external one. To investigate where in the brain an auditory event is "tagged" as originating from the external world, we used positron emission tomography to identify neural sites activated by both real hearing and hallucinations but not by imaginal hearing.
The neural mechanisms underlying hypnotic states and responses to hypnotic suggestions remain largely unknown and, to date, have been studied only with indirect methods. Here, the effects of hypnosis and suggestions to alter pain perception were investigated in hypnotizable subjects by using positron emission tomography (PET) measures of regional cerebral blood flow (rCBF) and electroencephalographic (EEG) measures of brain electrical activity.
In a single case study with positron emission tomography (PET) functional imaging, hypnotic paralysis activated similar brain areas to those in conversion hysteria, supporting the view that hypnosis and hysteria might share common neurophysiological mechanisms.
BACKGROUND: The neural mechanisms underlying the modulation of pain perception by hypnosis remain obscure. In this study, we used positron emission tomography in 11 healthy volunteers to identify the brain areas in which hypnosis modulates cerebral responses to a noxious stimulus. METHODS: The protocol used a factorial design with two factors: state (hypnotic state, resting state, mental imagery) and stimulation (warm non-noxious vs. hot noxious stimuli applied to right thenar eminence). Two cerebral blood flow scans were obtained with the 15O-water technique during each condition.
The study of pain integration, in vivo, within the human brain has been largely improved by the functional neuro-imaging techniques available for about 10 years. Positron Emission Tomography (PET), complemented by laser evoked potentials (LEP) and functional Magnetic Resonance Imaging (fMRI) can nowadays generate maps of physiological or neuropathic pain-related brain activity. LEP and fMRI complement PET by their better temporal resolution and the possibility of individual subject analyze.
OBJECTIVE: This study was designed to determine whether hypnosis can modulate color perception. Such evidence would provide insight into the nature of hypnosis and its underlying mechanisms. METHOD: Eight highly hypnotizable subjects were asked to see a color pattern in color, a similar gray-scale pattern in color, the color pattern as gray scale, and the gray-scale pattern as gray scale during positron emission tomography scanning by means of [(15)O]CO(2).
Pain and other phantom limb (PL) sensations have been proposed to be generated in the brain and to be reflected in activation of specific neural circuits. To test this hypothesis, hypnosis was used as a cognitive tool to alternate between the sensation of PL movement and pain in 8 amputees. Brain activity was measured using positron emission tomography. PL movement and pain were represented by a propagation of neuronal activity within the corresponding sensorimotor and pain-processing networks.