Neuroelectric evidences of top-down hypnotic modulation associated with somatosensory processing of sensory and limbic regions (original) (raw)
Related papers
Neurophysiological correlates of hypnotic analgesia
Contemporary Hypnosis, 2009
This short review describes recent advances in understanding hypnotic modulation of pain. Our current understanding of pain perception is followed by a critical review of the hypnotic analgesia studies using EEG, evoked potential and functional imaging methodologies.
Functional neuroanatomy of the hypnotic state
Journal of Physiology-paris, 2006
The neural mechanisms underlying hypnosis and especially the modulation of pain perception by hypnosis remain obscure. Using PET we first described the distribution of regional cerebral blood flow during the hypnotic state. Hypnosis relied on revivification of pleasant autobiographical memories and was compared to imaging autobiographical material in ''normal alertness''. The hypnotic state was related to the activation of a widespread set of cortical areas involving occipital, parietal, precentral, premotor, and ventrolateral prefrontal and anterior cingulate cortices. This pattern of activation shares some similarities with mental imagery, from which it mainly differs by the relative deactivation of precuneus. Second, we looked at the anti-nociceptive effects of hypnosis. Compared to the resting state, hypnosis reduced pain perception by approximately 50%. The hypnosis-induced reduction of affective and sensory responses to noxious thermal stimulation were modulated by the activity in the midcingulate cortex (area 24a 0 ). Finally, we assessed changes in cerebral functional connectivity related to hypnosis. Compared to normal alertness (i.e., rest and mental imagery), the hypnotic state, significantly enhanced the functional modulation between midcingulate cortex and a large neural network involved in sensory, affective, cognitive and behavioral aspects of nociception. These findings show that not only pharmacological but also psychological strategies for pain control can modulate the cerebral network involved in noxious perception.
Frontiers In Human Neuroscience, 2014
Altered state theories of hypnosis posit that a qualitatively distinct state of mental processing, which emerges in those with high hypnotic susceptibility following a hypnotic induction, enables the generation of anomalous experiences in response to specific hypnotic suggestions. If so then such a state should be observable as a discrete pattern of changes to functional connectivity (shared information) between brain regions following a hypnotic induction in high but not low hypnotically susceptible participants. Twenty-eight channel EEG was recorded from 12 high susceptible (highs) and 11 low susceptible (lows) participants with their eyes closed prior to and following a standard hypnotic induction. The EEG was used to provide a measure of functional connectivity using both coherence (COH) and the imaginary component of coherence (iCOH), which is insensitive to the effects of volume conduction. COH and iCOH were calculated between all electrode pairs for the frequency bands: delta (0.1-3.9Hz), theta (4-7.9Hz) alpha (8-12.9Hz), beta1 (13-19.9Hz), beta2 (20-29.9Hz) and gamma (30-45Hz). The results showed that there was an increase in theta iCOH from the pre-hypnosis to hypnosis condition in highs but not lows with a large proportion of significant links being focused on a central-parietal hub. There was also a decrease in beta1 iCOH from the pre-hypnosis to hypnosis condition with a focus on a fronto-central and an occipital hub that was greater in high compared to low susceptibles. There were no significant differences for COH or for spectral band amplitude in any frequency band. The results are interpreted as indicating that the hypnotic induction elicited a qualitative change in the organization of specific control systems within the brain for high as compared to low susceptible participants. This change in the functional organization of neural networks is a plausible indicator of the much theorized “hypnotic-state”.
Pain, 1998
Nociceptive electrical stimuli were applied to the sural nerve during hypnotically-suggested analgesia in the left lower limb of 18 highly susceptible subjects. During this procedure, the verbally reported pain threshold, the nociceptive flexion (RIII) reflex and late somatosensory evoked potentials were investigated in parallel with autonomic responses and the spontaneous electroencephalogram (EEG). The hypnotic suggestion of analgesia induced a significant increase in pain threshold in all the selected subjects. All the subjects showed large changes (i.e., by 20% or more) in the amplitudes of their RIII reflexes during hypnotic analgesia by comparison with control conditions. Although the extent of the increase in pain threshold was similar in all the subjects, two distinct patterns of modulation of the RIII reflex were observed during the hypnotic analgesia: in 11 subjects (subgroup 1), a strong inhibition of the reflex was observed whereas in the other seven subjects (subgroup 2) there was a strong facilitation of the reflex. All the subjects in both subgroups displayed similar decreases in the amplitude of late somatosensory evoked cerebral potentials during the hypnotic analgesia. No modification in the autonomic parameters or the EEG was observed. These data suggest that different strategies of modulation can be operative during effective hypnotic analgesia and that these are subject-dependent. Although all subjects may shift their attention away from the painful stimulus (which could explain the decrease of the late somatosensory evoked potentials), some of them inhibit their motor reaction to the stimulus at the spinal level, while in others, in contrast, this reaction is facilitated.
EEG and hypnotic susceptibility
Journal of Comparative and Physiological Psychology, 1970
Fifty-nine subjects volunteered for a "study of brain waves" subsequent to taking the Harvard Group Hypnotic Susceptibility Scale (HGS). The EEG autospectrum and cross spectrum were computed and further analyzed by stepwise regression techniques to determine EEG spectral parameters most related to hypnotic susceptibility. The results showed significant EEG prediction of HGS scores. The most predictive EEG parameters were from occipital autospectrum and occipital-vertex cross spectrum during conditions of visual fixation. The most predictive EEG frequencies were from the slow frequency range (5-8 Hz.). The results are discussed in terms of possible attentional mechanisms common to both EEG and hypnotic susceptibility.
Cerebral Mechanisms of Hypnotic Induction and Suggestion
Journal of Cognitive Neuroscience, 1999
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. The experimental conditions included a restful state (Baseline) followed by hypnotic relaxation alone (Hypnosis) and by hypnotic relaxation with suggestions for altered pain unpleasantness (Hypnosis-with-Suggestion). During each scan, the left hand was immersed in neutral (35°C) or painfully hot (47°C) water in the first two conditions and in painfully hot water in the last condition. Hypnosis was accompanied by significant increases in both occipital rCBF and delta EEG activity, which were highly correlated with each other (r = 0.70, p < ...
A psychophysiological differentiation between hypnotic behaviour and simulation
International Journal of Psychophysiology, 1988
Psychophysiological differentiation between conditions of hypnosis and simulation were examined with markers evolved from a series of experiments charting nemopsychophysiological accompaniments of hypnotic behaviour. Eighteen subjects participated in two sessions in which bilateral electrodermal activity was monitored to moderate intensity tones. Measurement in Session I, a Baseline-Control, of individual variation in rates of habituation of orienting responses, non-specific responses and tonic levels of skin conductance, enabled allocation of matched groups to Session II in which the same auditory stimuli were mixed with a taped hypnotic induction. Half the subjects were instructed to fake hypnosis and the others to comply. In session II the groups were differentiated as follows: (1) rate of habituation to the tones was retarded in the simulation condition and facilitated in the hypnosis condition compared with baseline; (2) the incidence of non-specific electrodermal responses was elevated in simulators after instructions to 'fake hypnosis'; (3) right-hand levels of skin conductance were elevated in simulators; (4) all but one subject in the hypnosis condition admitted to hearing the tones whereas all but one in the simulation condition claimed not to have heard them.
A working model of the neurophysiology of hypnosis: a review of evidence
Contemporary Hypnosis, 1998
Neuropsychophysiological evidence is reviewed testing a three-stage, top-down working model of the traditional hypnotic relaxation induction involving: (1) a thalamocortical attentional network engaging a left frontolimbic focused attention control system underpinning sensory fixation and concentration on the induction; (2) instatement of frontolimbic inhibitory systems through suggestions of tiredness at fixation and relaxation whereby anterior executive functions are suspended and directed by the induction; (3) engagement of right-sided temporoposterior functions through passive imagery and dreaming. A selectivity of action in high susceptibles was a hallmark of the studies. Increased Stroop interference coincided with maintenance of error detection and abolition of error evaluation potentials, interpreted as dissociation of cognitive and affective executive systems of the anterior cingulate. Verbal, category and design fluency tasks were dissociated with hypnosis centring on left anterior processes as seen in left lateral and medial reduced EEG connectivity. Limbic modulated electrodermal orienting responses and frontal modulated mismatch negativity waves were inhibited. Asymmetries in electrodermal and electrocortical responses to tones shifted to favour the right hemisphere, an asymmetry also seen in visual sensitivity. Haptic processing and visual sensitivity disclosed more distributed changes in medium susceptibles, while low susceptibles were characterized by poorer attentional functions at baseline and improvements through the induction.