Functional neuroanatomy of the hypnotic state

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'). 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.     

The thermal activity of the rabbit brain during the interaction of "animal hypnosis" and of the hunger dominant]

The character of interaction between two dominant foci (motivation hunger dominant and "animal hypnosis") which had been formed in the rabbit brain was ambiguous: the foci could either function simultaneously or compete. In the first case, summation food reactions were observed when the hunger dominant was tested during a hypnotic episode against the background of deep and continuous hypnotic state. Brain thermal activity was asymmetric the temperature being higher in the parieto-occipital areas of the left hemisphere. If the hypnosis inhibited the hunger dominant, summation reactions were absent and the brain temperature was higher in the parieto-occipital areas of the right hemisphere. In cases when despite the repeated immobilization sessions the hunger dominant prevented from induction of hypnosis, the left-hemisphere thermal dominance persisted against the background of general brain cooling.     

Hypnotic susceptibility and alterations in subjective experiences

Pavlov has described hypnosis as a partial sleep. A contemporary approach to this altered state of consciousness will be discussed. Under laboratory conditions subjective and behavioral data will be analyzed after hypnotic induction, shamanic trance and relaxation with listening to music. Role of different cortical regions will be shown after different hypnotic inductions as a function of hypnotic susceptibility. The importance of context will be underlined as an important factor in the possible alteration of consciousness.     

The Use of Hypnosis in the Treatment of Exhibitionism

The use of hypnosis in the treatment of exhibitionism is described in three patients in whom the condition had been present for more than five years. In each patient there was no subsequent recurrence of the exhibitionism once therapeutic suggestions had been made in a deep hypnotic trance, the follow-up period being respectively five years, four and a half years, and one year.The method of treatment and the results are discussed in terms of the concepts of behaviour therapy.It is concluded that with certain patients suffering from exhibitionism the use of hypnosis may well be one of the best methods of treatment, but considerable care should be exercised to exclude those patients with an underlying psychosis, mental defect or psychopathic condition. It is also noted that the efficacy of the treatment would appear to depend on achieving a satisfactory depth of hypnotic trance. If this is not reached, the results are less likely to be successful.     

The Impact of Hypnotic Suggestions on Reaction Times in Continuous Performance Test in Adults with ADHD and Healthy Controls

Attention is one of the key factors in both hypnotic processes and patients with ADHD. In addition, the brain areas associated with hypnosis and ADHD overlap in many respects. However, the use of hypnosis in ADHD patients has still received only minor attention in research. The main purpose of the present work was to investigate whether hypnosis and hypnotic suggestions influence the performance of adult ADHD (n = 27) and control participants (n = 31) in the continuous performance test (CPT). The hypnotic susceptibility of the participants was measured by the Harvard Group Scale of Hypnotic Susceptibility (HGSHS:A) and the attentional task was a three minute long auditory version of the CPT. The CPT task was administered four times: before hypnosis (CPT1), after a hypnotic induction (CPT2), after suggestions about speed and accuracy (CPT3), and after the termination of hypnosis (CPT4). The susceptibility of the groups measured by HGSHS:A did not differ. There was a statistically significant decrease in reaction times in both ADHD and control groups between CPT2 and CPT3. The differences between CPT1 and CPT2, even though non-significant, were different in the two groups: in the ADHD group reaction times decreased whereas in the control group they increased. Both groups made very few errors in the short CPT. This study indicates that hypnotic suggestions have an effect on reaction times in the sustained attention task both in adult ADHD patients and control subjects. The theoretical and clinical implications are discussed.     

Paradoxical experience of hypnotic analgesia in low hypnotizable fibromyalgic patients

The study investigated the differences in pain perception in highly (Highs) and low (Lows) hypnotizable patients with chronic benign pain undergoing hypnotic suggestions of analgesia. Self reports of pain intensity were collected in different groups of fibromyalgic patients: (1) Highs and Lows during pre-hypnosis, neutral hypnosis, suggestions for analgesia, posthypnotic conditions; (2) Lows during suggestions for analgesia administered after a mental stress instead of neutral hypnosis; (3) healthy Lows receiving nociceptive stimulation during hypnotic relaxation and suggestions of analgesia. The results showed that Highs and Lows differed in their response to suggestions, but significant analgesia was reported also by Lows. These individuals did not report any difference in pain perception between the sessions including mental stress and hypnotic relaxation. No change in pain perception was observed in healthy Lows during nociceptive stimulation associated with relaxation and suggestions for analgesia. In conclusion, the presence of chronic pain seems to be responsible for the paradoxical response of non hypnotizable patients to hypnotic suggestions.     

The Effects of Hypnotherapy on Homosexuality

Fifteen homosexuals were treated with hypnosis. The patients were selected from a general psychiatric practice and had a long history of confirmed homosexual behaviour and showed no evidence of organic or psychotic illness. The type of hypnotic induction attempted in all cases is described. In those where a satisfactory depth of hypnotic trance was achieved a change in sexual orientation was suggested to the patient.Before therapy, each patient was assessed using the Kinsey scale. Results were evaluated in terms of the patient''s subsequent behaviour and his subjective feelings. Of the 15 patients, three showed no improvement, four showed a mild improvement and eight showed a marked improvement. There was a significant correlation between the depth of hypnosis achieved and the therapeutic outcome. Those patients who reached a deep level of hypnotic trance were most likely to show a marked improvement. There were no significant correlations with other factors such as degree of homosexuality as measured on the Kinsey scale and the patient''s marital status.Treatment of homosexuals with hypnosis may produce more satisfactory results than those obtainable by other means. The best results are likely to be achieved in patients who are good hypnotic subjects.     

JM-1232(−) and propofol,a new combination of hypnotics with short-acting and non-cumulative preferable properties

Drug interactions are significant in anesthesiology because drug combinations can potentially possess novel properties. The pharmacological advantages of a new combination of the benzodiazepine receptor agonist JM-1232(−) and propofol were investigated in mice. Male adult mice were administered JM-1232(−) or propofol or combinations of the two drugs intravenously. Loss of the righting reflex was evaluated as achieving hypnosis, and the time until recovery of the reflex was measured as hypnosis time. After determining the ED₅₀, doses double and triple the ED₅₀ of propofol were injected with JM-1232(−) to compare hypnosis time. The injections were repeated four times, and the hypnosis times were compared. Flumazenil was administered separately immediately after the last dose was injected. The ED₅₀ values ([95% confidence interval]) for hypnosis were 3.76 [3.36–4.10] for JM-1232(−) and 9.88 [8.03–11.58] mg kg⁻¹ for propofol. Co-administration of 0.5 and 1 mg kg⁻¹ JM-1232(−) reduced the ED₅₀ values of propofol to 1.76 [1.21–2.51] and 1.00 [0.46–1.86] mg kg⁻¹, respectively. The drug combination for hypnosis produced a supra-additive interaction. Hypnosis time was significantly shorter in the groups given the mixtures compared to each hypnotic administered alone. After repeated injections, hypnosis time with the mixtures showed smaller prolongation than that with the hypnotic alone. Flumazenil completely restored the recovery time after anesthesia. The combination of JM-1232(−) and propofol showed a supra-additive interaction, and the reduced hypnotic dose contributed to a faster recovery even after multiple injections.     

The interhemispheric brain asymmetry of the rabbit in a state of "animal hypnosis"]

By the method of forced immobilization the rabbits were brought into the state of "animal hypnosis" (immobilization reflex), and their ECoG was recorded, which was further processed on the computer. It was found that during hypnosis a functional interhemispheric brain asymmetry was developed in rabbits with activity predominance in the right hemisphere. The "animal hypnosis" is a phasic process: in the ECoG of the rabbit under hypnosis a regular alternation of delta and theta activity takes place. Electrophysiological reconstructions in the rabbit brain during the change of its functional state correlate with the brain thermal reactions, revealed earlier.     

Hypnosis and modern frontal-lobe concepts--a sketch for a review and an invitation to one particularly promising field

The present paper intends to briefly review the most important concepts of the modern neuropsychology of the frontal lobes, and to relate these findings to the phenomenology usually encountered in hypnosis research and practice. The frontal lobes have been studied very intensively during the last several years and some of the results, including the syndromes described in frontal-lobe lesions and psychiatric patients, demonstrate striking similarity with hypnotic phenomena. Based on these similarities, an alternative neuropsychophysiological definition of hypnosis/suggestion is proposed, viewing hypnosis/suggestion as the process of external manipulation with frontal-lobe functions with consequent effects upon the entire brain potential of the subject.     

Hypnosis modelling in neural networks

In the framework of the neural network theory effects similar to hypnotic displays are constructed. They are based on the associative paradigm involving non-linear interaction of excitatory and inhibitory channels with synaptic memory. The non-linearity of long-term memorizing processes may cause effects exhibited by blind spots, which are interpreted as the first stage of hypnosis. More complicated phenomena are discussed in terms of a two-layer network.     

Mechanism of the discontinuance of work as a consequence of fatigue according to the change in the electromyogram in a hypnotic state]

A study was made of the changes in the bioelectrical activity of the muscles in the course of local static work up to "refusal" under the usual conditions and under condition of inhibition of the program-control function of the cortex (during the somnambulistic stage of hypnosis). Experimental results indicated that during the hypnotic state the time of persistence of the static effort doubled in comparison with control; the bioelectrical activity increased 1 1/2-2 times, and in individual experiments--3--4 times. In the light of the data obtained the mechanism of formation of "refusal" to work could be viewed as an active arrest of the activity of the central formations realizing the program-control functions.     

Blood pressure responses to hypnotic and nonhypnotic suggestions in normotensive subjects

Forty normotensive subjects participated on a voluntary basis in a study designed to compare the effect of suggestions on blood pressure (BP). Two experimental groups received suggestions presumed to be specific in lowering or raising BP after simple relaxation (relaxation group) or hypnotic induction (hypnotic group). A control group was used to record the BP changes over time. The time variable was significant for both systolic (SBP) and diastolic blood pressure (DBP). Induction procedures (hypnosis or relaxation) resulted in significant decreases in DBP in both experimental groups. In the control group there was a significant decrease in SBP. A specific suggestion to increase the BP resulted only in DBP increase in the hypnotic group. This group also gave an increase of both SBP and DBP over the entire experiment, whereas the relaxation group resulted in a significant decrease in SBP. There was no significant group variable, indicating no differences between the groups. Further research is needed to enable firm conclusions of the effect of suggestions on BP.     

Learning in trance: Functional brain imaging studies and neuropsychology

This study examined the fundamental question, whether verbal memory processing in hypnosis and in the waking state is mediated by a common neural system or by distinct cortical areas. Seven right-handed volunteers (25.4 years, sd 3.1) with high-hypnotic susceptibility scores were PET-scanned while encoding/retrieving word associations either in hypnosis or in the waking state. Word-pairs were visually presented and highly imaginable, but not semantically related (e.g. monkey-street). The presentation of pseudo-words served as a reference condition. An emission scan was recorded after each intravenous administration of O-15 water. Encoding under hypnosis was associated with more pronounced bilateral activations in the occipital cortex and the prefrontal areas as compared to learning in the waking state. During memory retrieval of word-pairs which had been previously learned under hypnosis, activations were found in the occipital lobe and the cerebellum. Under both experimental conditions precuneus and prefrontal cortex showed a consistent bilateral activation which was most distinct when the learning had taken place under hypnosis. In order to further analyze the effect of hypnosis on imagery-mediated learning, we administered sets of high-imagery word-pairs and sets of abstract words. In the first experimental condition word-pair associations were presented visually. In the second condition it was found that highly hypnotisable persons recalled significantly more high-imagery words under hypnosis as compared to low-hypnotisables both in the visual and auditory modality. Furthermore, high-imagery words were also better recalled by the highly hypnotisable subjects during the non-hypnotic condition. The memory effect was consistently present under both, immediate and delayed recall conditions. Taken together, the findings advance our understanding of the neural representation that underlies hypnosis and the neuropsychological correlates of hypnotic susceptibility.     

The structure of dependent relationship between neurons in the sensorimotor cortex of the left and right hemisphere in rabbits during immobilizing catatonia

Relations between activities of neurons simultaneously recorded in the left and right sensorimotor brain cortices of rabbits were analyzed in a series of experiments before the induction of the immobilization state ("animal hypnosis"), in the state of immobilization, and after its termination. The total baseline percent of significant correlations between activities of neighboring (within 50 microns) neurons in the left hemisphere was significantly lower than in the right hemisphere. This characteristic of the left hemisphere changed neither in the immobilization state nor after its termination. In the right-hemisphere cortex, the total percent of correlations between neighboring neurons significantly decreased during immobilization and returned to the baseline level after the termination of this state. In contrast, percent of correlations between the activities of remote (within 500 microns) neurons in the right-hemisphere did not change during immobilization, whereas in the left cortex it changed significantly and reached its baseline level after the normalization of rabbit's state. Further analysis showed that the revealed cortical interhemispheric asymmetry is underlain by asymmetric activities of individual neurons and small neuronal populations. Thus, for example, changes in the structure of interneuronal correlations in cortical microareas of the left and macroareas of the right hemispheres could be of different directions, whereas correlated activities in microareas of the right and macroareas of the left-hemispheres could change synergetically. In other words, asymmetry was revealed at different levels of neuronal integration (neuronal pairs, micro- or macrogroups of neurons). This finding testifies to a mosaic character of neuronal activity, which finally results in the general functional asymmetry during the "animal hypnosis". Certain changes in the structure of functional relations between neurons of the sensorimotor cortex that developed in the state of "animal hypnosis" persisted and even augmented after the termination of this state.     

Sensitivity and Specificity of Hypnosis Effects on Gastric Myoelectrical Activity

Objectives

The effects of hypnosis on physiological (gastrointestinal) functions are incompletely understood, and it is unknown whether they are hypnosis-specific and gut-specific, or simply unspecific effects of relaxation.

Design

Sixty-two healthy female volunteers were randomly assigned to either a single session of hypnotic suggestion of ingesting an appetizing meal and an unappetizing meal, or to relax and concentrate on having an appetizing or unappetizing meal, while the electrogastrogram (EGG) was recorded. At the end of the session, participants drank water until they felt full, in order to detect EGG-signal changes after ingestion of a true gastric load. During both conditions participants reported their subjective well-being, hunger and disgust at several time points.

Results

Imagining eating food induced subjective feelings of hunger and disgust as well as changes in the EGG similar to, but more pronounced than those seen with a real gastric water load during both hypnosis and relaxation conditions. These effects were more pronounced when imagining an appetizing meal than with an unappetizing meal. There was no significant difference between the hypnosis and relaxation conditions.

Conclusion

Imagination with and without hypnosis exhibits similar changes in subjective and objective measures in response to imagining an appetizing and an unappetizing food, indicating high sensitivity but low specificity.     

"Animal hypnosis" and defensive dominant,behavioral aspect

A stationary excitation focus produced in the sensorimotor cortex of a rabbit by rhythmic electrodermal paw stimulation was manifested in the reaction to a testing sound stimulus earlier indifferent for the animal. Regardless of the stimulated paw (left or right), reactions to the testing stimuli appeared approximately in the equal percent of cases (70.7% and 71.5%, respectively). After a single-trial induction of the "animal hypnosis" state, it was difficult to produce the dominant focus by simulation of the left paw, whereas the results of the right-paw stimulation did not differ from those obtained during control stimulation. Consequently, the influence of hypnosis on defensive stationary excitation foci in different hemispheres was not the same.     

Motor polarization dominance and "animal hypnosis"

Two kinds of dominanta were simultaneously formed under conditions of chronic experiments in rabbits. The motor polarization dominanta was formed under exposure of the right sensorimotor cortex of an animal to direct anodic current, and the state of "animal hypnosis" (the second dominanta) was induced. Animal behavior and electrophysiological characteristics were recorded. It was shown that the "animal hypnosis" induced at the optimum of the right motor polarization dominanta inhibited the motor reaction of the "dominant" extremity to testing stimuli. After the "animal hypnosis session, exposure of the right sensorimotor cortex to anodic current produced the latent excitation focus, which did not reach the level of summation. Two days later, exposure to testing stimuli developed the latent foci at first in the right cortex and then in subcortical structures. In the course of recovery of the motor polarization dominanta and its further change for the state characteristic of the "animal hypnosis", the patterns of cortical EEG coherence in the delta range typical of each kind of dominanta alternated in parallel with the time course of state changes.     

Method for Simultaneous fMRI/EEG Data Collection during a Focused Attention Suggestion for Differential Thermal Sensation

In the present work, we demonstrate a method for concurrent collection of EEG/fMRI data. In our setup, EEG data are collected using a high-density 256-channel sensor net. The EEG amplifier itself is contained in a field isolation containment system (FICS), and MRI clock signals are synchronized with EEG data collection for subsequent MR artifact characterization and removal. We demonstrate this method first for resting state data collection. Thereafter, we demonstrate a protocol for EEG/fMRI data recording, while subjects listen to a tape asking them to visualize that their left hand is immersed in a cold-water bath and referred to, here, as the cold glove paradigm. Thermal differentials between each hand are measured throughout EEG/fMRI data collection using an MR compatible temperature sensor that we developed for this purpose. We collect cold glove EEG/fMRI data along with simultaneous differential hand temperature measurements both before and after hypnotic induction. Between pre and post sessions, single modality EEG data are collected during the hypnotic induction and depth assessment process. Our representative results demonstrate that significant changes in the EEG power spectrum can be measured during hypnotic induction, and that hand temperature changes during the cold glove paradigm can be detected rapidly using our MR compatible differential thermometry device.     

Interregional cortical interactions at different stages of natural sleep and the hypnotic state: EEG evidence

The characteristic patterns of EEG spatial organization at different stages of natural sleep and the hypnotic state were studied in 26 volunteers aged 18–22 years. EEGs were recorded using 12 monopolar leads, and EEG cross-correlation coefficient matrices were calculated for consecutive epochs (4 and 8 s). Matrices averaged for each state were treated using factor analysis. The EEG correlation matrices were compared element by element for the states studied and the waking state. Relatively similar changes in the spatial structure of EEG correlations were observed at different stages of natural sleep, with the correlations tending to intensify, especially in the posterior temporal region of the right hemisphere. In the light and deep (somnambular) phases of hypnosis, the interaction between cortical zones that was characteristic of distant relationships of the EEGs of frontal regions, especially the posterior inferior frontal region of the right hemisphere, decreased. The systemic reorganization of the interregional EEG correlations during natural sleep was considerably more pronounced than in the hypnotic state. Notwithstanding, the highly orderly spatial organization of the cortical biopotential field that was typical of the waking state was retained at different stages of natural sleep and hypnosis. Thus, the coordination of the activities of distant nerve centers oriented to providing for a certain function or maintaining a certain functional state occurs against the background of a relatively invariant pattern of interregional integration at the level of the whole brain.Translated from Fiziologiya Cheloveka, Vol. 31, No. 2, 2005, pp. 34–48.Original Russian Text Copyright © 2005 by A. Shepovalnikov, Tsitseroshin, Rozhkov, Galperina, Zaitseva, R. Shepovalnikov.