Cerebral mechanisms of hypnotic induction and suggestion

The impacts of hypnotic susceptibility on chaotic dynamics of EEG signals during standard tasks of Waterloo-Stanford Group Scale

Chaotic features of hypnotic EEG (electroencephalograph), recorded during standard tasks of Waterloo-Stanford Group Scale of hypnotic susceptibility (WSGS), were used to investigate the underlying dynamic of tasks and analyse the effect of hypnotic depth and concentration on EEG signals. Results demonstrate: (1) More efficiency of Higuchi dimension in comparison with Correlation dimension to distinguish subjects from different hypnotizable groups, (2) Channels with significantly different chaotic features among people from various hypnotizability levels in tasks, (3) High level of consistency among discriminating channels of tasks with function of brain's lobes, (4) Most affectability of medium hypnotizable subjects and (5) Rise in fractal dimensions due to increase in hypnosis depth.

Towards an integrative theory of consciousness: part 1 (neurobiological and cognitive models)

The study of consciousness is poised today at interesting crossroads. There has been a surge of research into various neurobiological underpinnings of consciousness in the past decade. The present article looks at the theories regarding this complex phenomenon, especially the ones that neurobiology, cognitive neuroscience and cognitive psychology have to offer. We will first discuss the origin and etymology of word consciousness and its usage. Neurobiological correlates of consciousness are discussed with structures like the ascending reticular activating system, the amygdala, the cerebellum, the thalamus, the frontoparietal circuits, the prefrontal cortex and the precuneus. The cellular and microlevel theories of consciousness and cerebral activity at the neuronal level contributing to consciousness are highlighted, along with the various theories posited in this area. The role of neuronal assemblies and circuits along with firing patterns and their ramifications for the understanding of consciousness are discussed. A section on the role of anaesthesia and its links to consciousness is presented, along with details of split-brain studies in consciousness and altered states of awareness, including the vegetative states. The article finally discusses the progress cognitive psychology has made in identifying and theorising various perspectives of consciousness, perceptual awareness and conscious processing. Both recent and past researches are highlighted. The importance and salient features of each theory are discussed along with the pitfalls, if present. A need for integration of various theories to understand consciousness from a holistic perspective is stressed, to enable one to reach a theory that explains the ultimate neurobiology of consciousness.

Tranceformations: hypnosis in brain and body

In this review, the role of hypnosis and related psychotherapeutic techniques are discussed in relation to the anxiety disorders. In particular, anxiety is addressed as a special form of mind/body problem involving reverberating interaction between mental and physical distress. The history of hypnosis as a therapeutic discipline is reviewed, after which neurobiological evidence of the effect of hypnosis on modulation of perception in the brain. Specific brain regions involved in hypnosis are reviewed, notably the dorsal anterior cingulate gyrus and the dorsolateral prefrontal cortex. The importance of hypnotizability as a trait, stable variability in hypnotic responsiveness, is discussed. Analogies between the hypnotic state and dissociative reactions to trauma are presented, and the uses of hypnosis in treating posttraumatic stress disorder, stressful situations, and phobias as well as outcome data are reviewed. Effects of hypnosis on control of somatic processes are discussed, and then effects of psychosocial support involving Supportive-Expressive Group Therapy and hypnosis on survival time for cancer patients are evaluated. The evidence indicates an important role for hypnosis in managing anxiety disorders and anxiety related to medical illness.

Hypnotic susceptibility modulates brain activity related to experimental placebo analgesia

Identifying personality traits and neural signatures that predict placebo responsiveness is important, both on theoretical and practical grounds. In the present functional magnetic resonance imaging (fMRI) study, we performed multiple-regression interaction analysis to investigate whether hypnotic susceptibility (HS), a cognitive trait referring to the responsiveness to suggestions, explains interindividual differences in the neural mechanisms related to conditioned placebo analgesia in healthy volunteers. HS was not related to the overall strength of placebo analgesia. However, we found several HS-related differences in the patterns of fMRI activity and seed-based functional connectivity that accompanied placebo analgesia. Specifically, in subjects with higher HS, the placebo response was related to increased anticipatory activity in a right dorsolateral prefrontal cortex focus, and to reduced functional connectivity of that focus with brain regions related to emotional and evaluative pain processing (anterior mid-cingulate cortex/medial prefrontal cortex); an opposite pattern of fMRI activity and functional connectivity was found in subjects with lower HS. During pain perception, activity in the regions reflecting attention/arousal (bilateral anterior thalamus/left caudate) and self-related processing (left precuneus and bilateral posterior temporal foci) was negatively related to the strength of the analgesic placebo response in subjects with higher HS, but not in subjects with lower HS. These findings highlight HS influences on brain circuits related to the placebo analgesic effects. More generally, they demonstrate that different neural mechanisms can be involved in placebo responsiveness, depending on individual cognitive traits.

Hypnosis in the right hemisphere

Speculations about the neural substrates of hypnosis have often focused on the right hemisphere (RH), implying that RH damage should impair hypnotic responsiveness more than left-hemisphere (LH) damage. The present study examined the performance of a patient who suffered a stroke destroying most of his LH, on slightly modified versions of two hypnotizability scales. This patient was at least modestly hypnotizable, as indicated in particular by the arm rigidity and age regression items, suggesting that hypnosis can be mediated by the RH alone - provided that the language capacities normally found in the LH remain available. A further study of 16 patients with unilateral strokes of the LH or RH found no substantial differences in hypnotizability between the two groups. Future neuropsychological studies of hypnosis might explore the dorsal/ventral or anterior/posterior dichotomies, with special emphasis on the role of prefrontal cortex.

An eye for an I: a 35-year-old woman with fluctuating oculomotor deficits and dissociative identity disorder

Physiologic changes, including neurological or pseudo-neurological symptoms, occur across identity states in dissociative identity disorder DID) and can be objectively measured. The idea that dissociative phenomena might be associated with changes in brain function is consistent with research on the brain effects of hypnosis. The authors report a case of psycho-physiologic differences among 4 alter personalities manifested by a 35-year-old woman with DID. Differences in visual acuity, frequency of pendular nystagmus, and handedness were observed in this patient both when the alter personalities appeared spontaneously and when elicited under hypnosis. The authors consider several diagnostic possibilities for these findings and discuss whether prevailing treatment recommendations for DID patients could possibly be modified to ameliorate such visual and neurologic symptoms.

Functional brain basis of hypnotizability

CONTEXT

Focused hypnotic concentration is a model for brain control over sensation and behavior. Pain and anxiety can be effectively alleviated by hypnotic suggestion, which modulates activity in brain regions associated with focused attention, but the specific neural network underlying this phenomenon is not known.

OBJECTIVE

To investigate the brain basis of hypnotizability.

DESIGN

Cross-sectional, in vivo neuroimaging study performed from November 2005 through July 2006.

SETTING

Academic medical center at Stanford University School of Medicine.

PATIENTS

Twelve adults with high and 12 adults with low hypnotizability.

MAIN OUTCOME MEASURES

Functional magnetic resonance imaging to measure functional connectivity networks at rest, including default-mode, salience, and executive-control networks; structural T1 magnetic resonance imaging to measure regional gray and white matter volumes; and diffusion tensor imaging to measure white matter microstructural integrity.

RESULTS

High compared with low hypnotizable individuals had greater functional connectivity between the left dorsolateral prefrontal cortex, an executive-control region of the brain, and the salience network composed of the dorsal anterior cingulate cortex, anterior insula, amygdala, and ventral striatum, involved in detecting, integrating, and filtering relevant somatic, autonomic, and emotional information using independent component analysis. Seed-based analysis confirmed elevated functional coupling between the dorsal anterior cingulate cortex and the dorsolateral prefrontal cortex in high compared with low hypnotizable individuals. These functional differences were not due to any variation in brain structure in these regions, including regional gray and white matter volumes and white matter microstructure.

CONCLUSIONS

Our results provide novel evidence that altered functional connectivity in the dorsolateral prefrontal cortex and dorsal anterior cingulate cortex may underlie hypnotizability. Future studies focusing on how these functional networks change and interact during hypnosis are warranted.

Experimental pain ratings and reactivity of cortisol and soluble tumor necrosis factor-α receptor II following a trial of hypnosis: results of a randomized controlled pilot study

OBJECTIVE

Current evidence supports the efficacy of hypnosis for reducing the pain associated with experimental stimulation and various acute and chronic conditions; however, the mechanisms explaining how hypnosis exerts its effects remain less clear. The hypothalamic-pituitary-adrenal (HPA) axis and pro-inflammatory cytokines represent potential targets for investigation given their purported roles in the perpetuation of painful conditions; yet, no clinical trials have thus far examined the influence of hypnosis on these mechanisms.

DESIGN

Healthy participants, highly susceptible to the effects of hypnosis, were randomized to either a hypnosis intervention or a no-intervention control. Using a cold pressor task, assessments of pain intensity and pain unpleasantness were collected prior to the intervention (Pre) and following the intervention (Post) along with pain-provoked changes in salivary cortisol and the soluble tumor necrosis factor-α receptor II (sTNFαRII).

RESULTS

Compared with the no-intervention control, data analyses revealed that hypnosis significantly reduced pain intensity and pain unpleasantness. Hypnosis was not significantly associated with suppression of cortisol or sTNFαRII reactivity to acute pain from Pre to Post; however, the effect sizes for these associations were medium-sized.

CONCLUSIONS

Overall, the findings from this randomized controlled pilot study support the importance of a future large-scale study on the effects of hypnosis for modulating pain-related changes of the HPA axis and pro-inflammatory cytokines.

The use of functional neuroimaging to evaluate psychological and other non-pharmacological treatments for clinical pain

A large number of studies have provided evidence for the efficacy of psychological and other non-pharmacological interventions in the treatment of chronic pain. While these methods are increasingly used to treat pain, remarkably few studies focused on the exploration of their neural correlates. The aim of this article was to review the findings from neuroimaging studies that evaluated the neural response to distraction-based techniques, cognitive behavioral therapy (CBT), clinical hypnosis, mental imagery, physical therapy/exercise, biofeedback, and mirror therapy. To date, the results from studies that used neuroimaging to evaluate these methods have not been conclusive and the experimental methods have been suboptimal for assessing clinical pain. Still, several different psychological and non-pharmacological treatment modalities were associated with increased pain-related activations of executive cognitive brain regions, such as the ventral- and dorsolateral prefrontal cortex. There was also evidence for decreased pain-related activations in afferent pain regions and limbic structures. If future studies will address the technical and methodological challenges of today's experiments, neuroimaging might have the potential of segregating the neural mechanisms of different treatment interventions and elucidate predictive and mediating factors for successful treatment outcomes. Evaluations of treatment-related brain changes (functional and structural) might also allow for sub-grouping of patients and help to develop individualized treatments.

fMRI evidence of degeneration-induced neuropathic pain in diabetes: enhanced limbic and striatal activations

Persistent neuropathic pain due to peripheral nerve degeneration in diabetes is a stressful symptom; however, the underlying neural substrates remain elusive. This study attempted to explore neuroanatomical substrates of thermal hyperalgesia and burning pain in a diabetic cohort due to pathologically proven cutaneous nerve degeneration (the painful group). By applying noxious 44°C heat stimuli to the right foot to provoke neuropathic pain symptoms, brain activation patterns were compared with those of healthy control subjects and patients with a similar degree of cutaneous nerve degeneration but without pain (the painless group). Psychophysical results showed enhanced affective pain ratings in the painful group. After eliminating the influence of different pain intensity ratings on cerebral responses, the painful group displayed augmented responses in the limbic and striatal structures, including the perigenual anterior cingulate cortex (ACC), superior frontal gyrus, medial thalamus, anterior insular cortex, lentiform nucleus (LN), and premotor area. Among these regions, blood oxygen level-dependent (BOLD) signals in the ACC and LN were correlated with pain ratings to thermal stimulations in the painful group. Furthermore, activation maps of a simple regression analysis as well as a region of interest analysis revealed that responses in these limbic and striatal circuits paralleled the duration of neuropathic pain. However, in the painless group, BOLD signals in the primary somatosensory cortex and ACC were reduced. These results suggest that enhanced limbic and striatal activations underlie maladaptive responses after cutaneous nerve degeneration, which contributed to the development and maintenance of burning pain and thermal hyperalgesia in diabetes.

The facilitating effect of clinical hypnosis on motor imagery: an fMRI study

Hypnosis is increasingly being employed in therapy of neurologically impaired patients. In fact, reports from neuropsychological practice point out that neurological patients with a loss of motor abilities achieve successful rehabilitation by means of motor imagery during hypnosis. This approach was shown to be effective even if the patients' ability to imagine movements was impaired or lost. The underlying mechanisms of "how" and "where" hypnosis affects the brain, however, are largely unknown. To identify the brain areas involved in motor imagery under hypnosis, we conducted an fMRI study in which we required healthy human subjects either to imagine or to execute repetitive finger movements during a hypnotic trance. We observed fMRI-signal increases exclusively related to hypnosis in the left superior frontal cortex, the left anterior cingulate gyrus and left thalamus. While the superior frontal cortex and the anterior cingulate were active related more to movement performance than to imagery, the thalamus was activated only during motor imagery. These areas represent central nodes of the salience network linking primary and higher motor areas. Therefore, our data substantiate the notion that hypnosis enhances motor imagery.

Posthypnotic state changes and flashbacks: analogous processes?

Careful study of the posttraumatic stress disorder and hypnosis literatures reveals some parallels between posttraumatic flashbacks and responses to posthypnotic suggestions. Highly susceptible subjects can slip into hypnosis spontaneously and accept and respond to implied or inadvertent suggestions, some of which may operate in a manner equivalent to posthypnotic suggestions. Later, exposure to appropriate cues may trigger an intrusive revivification of the hypnotic state in which the suggestion occurred. This sequence of events closely resembles the sequence of reactions that some individuals have to trauma that ultimately leads to flashbacks. Thus, flashbacks may be conceived of as intrusive posttraumatic revivifications of trauma-induced hypnosis-like states that are reactivated by trauma-reminiscent cues operating similarly to posthypnotic signals. Implications of viewing flashbacks in this way, especially if this view is supported by future research, could include significant changes in how posttraumatic stress disorder is conceptualized and treated.

Hypnotizability-related differences in written language

The study analyzed the writing products of subjects with high (highs) and low (lows) hypnotizability. The participants were asked to write short texts in response to highly imaginative scenarios in standard conditions. The texts were processed through computerized and manual methods. The results showed that the highs' texts were more sophisticated due to a higher number of abstract nouns, more intense and imaginative due to a larger number of similes, metaphors, and onomatopoeias, and less detailed due to a higher nouns-to-adjectives ratio. The differences in the use of abstract nouns and highly imageable expressions are discussed in relation to the preeminent left-hemisphere activity of highs during wakefulness and to a possibly different involvement of the precuneus, which is involved in hypnotic phenomena.

Fractal analysis of EEG upon auditory stimulation during waking and hypnosis in healthy volunteers

The authors tested fluctuation analyses (DFA) of EEGs upon auditory stimulation in waking and hypnotic states as related to topography and hypnotizability. They administered the Hypnotic Induction Profile (HIP), Dissociation Experience Scale, and Tellegen Absorption Scale to 10 healthy volunteers and measured subjects' EEGs while the subjects listened to sounds, either selecting or ignoring tones of different decibels, in waking and hypnotic states. DFA scaling exponents were closest to 0.5 when subjects reported the tones in the hypnotic state. Different DFA values at C3 showed significant positive correlations with the HIP eye-roll sign. Adding to the literature supporting the state theory of hypnosis, the DFA values at F3 and C3 showed significant differences between waking and hypnotic states. Application of auditory stimuli is useful for understanding neurophysiological characteristics of hypnosis using DFA.

EEG sLORETA functional imaging during hypnotic arm levitation and voluntary arm lifting

This study (N = 37 with high, medium, and low hypnotizables) evaluated depth reports and EEG activity during both voluntary and hypnotically induced left-arm lifting with sLORETA functional neuroimaging. The hypnotic condition was associated with higher activity in fast EEG frequencies in anterior regions and slow EEG frequencies in central-parietal regions, all left-sided. The voluntary condition was associated with fast frequency activity in right-hemisphere central-parietal regions and slow frequency activity in left anterior regions. Hypnotizability did not have a significant effect on EEG activity, but hypnotic depth correlated with left hemisphere increased anterior slow EEG and decreased central fast EEG activity. Hypnosis had a minimal effect on depth reports among lows, a moderate one among mediums, and a large one among highs. Because only left-arm data were available, the full role of the hemispheres remains to be clarified.

Neurocognition under hypnosis: findings from recent functional neuroimaging studies

Functional neuroimaging studies show that hypnosis affects attention by modulating anterior cingulate cortex activation and uncoupling conflict monitoring and cognitive control function. Considering functional changes in the activation of the occipital and temporal cortices, precuneus, and other extrastriate visual areas, which account for hypnosis-induced altered reality perception, the role of mental imagery areas appears to be central under hypnosis. This is further stressed by the fact that motor commands are processed differently in the normal conscious state, deviating toward the precuneus and extrastriate visual areas. Functional neuroimaging also shows that posthypnotic suggestions alter cognitive processes. Further research should investigate the effects of hypnosis on other executive functions and personality measures.

Neuroimaging of the periaqueductal gray: state of the field

This review and meta-analysis aims at summarizing and integrating the human neuroimaging studies that report periaqueductal gray (PAG) involvement; 250 original manuscripts on human neuroimaging of the PAG were identified. A narrative review and meta-analysis using activation likelihood estimates is included. Behaviors covered include pain and pain modulation, anxiety, bladder and bowel function and autonomic regulation. Methods include structural and functional magnetic resonance imaging, functional connectivity measures, diffusion weighted imaging and positron emission tomography. Human neuroimaging studies in healthy and clinical populations largely confirm the animal literature indicating that the PAG is involved in homeostatic regulation of salient functions such as pain, anxiety and autonomic function. Methodological concerns in the current literature, including resolution constraints, imaging artifacts and imprecise neuroanatomical labeling are discussed, and future directions are proposed. A general conclusion is that PAG neuroimaging is a field with enormous potential to translate animal data onto human behaviors, but with some growing pains that can and need to be addressed in order to add to our understanding of the neurobiology of this key region.

Sex similarities and differences in pain-related periaqueductal gray connectivity

This study investigated sex similarities and differences in pain-related functional connectivity in 60 healthy subjects. We used functional magnetic resonance imaging and psychophysiological interaction analysis to investigate how exposure to low vs high experimental pain modulates the functional connectivity of the periaqueductal gray (PAG). We found no sex differences in pain thresholds, and in both men and women, the PAG was more functionally connected with the somatosensory cortex, the supplemental motor area, cerebellum, and thalamus during high pain, consistent with anatomic predictions. Twenty-six men displayed a pain-induced increase in PAG functional connectivity with the amygdala caudate and putamen that was not observed in women. In an extensive literature search, we found that female animals have been largely overlooked when the connections between the PAG and the amygdala have been described, and that women are systematically understudied with regard to endogenous pain inhibition. Our results emphasize the importance of including both male and female subjects when studying basic mechanisms of pain processing, and point toward a possible sex difference in endogenous pain inhibition.

Abnormal parietal function in conversion paresis

The etiology of medically unexplained symptoms such as conversion disorder is poorly understood. This is partly because the interpretation of neuroimaging results in conversion paresis has been complicated by the use of different control groups, tasks and statistical comparisons. The present study includes these different aspects in a single data set. In our study we included both normal controls and feigners to control for conversion paresis. We studied both movement execution and imagery, and we contrasted both within-group and between-group activation. Moreover, to reveal hemisphere-specific effects that have not been reported before, we performed these analyses using both flipped and unflipped data. This approach resulted in the identification of abnormal parietal activation which was specific for conversion paresis patients. Patients also showed reduced activity in the prefrontal cortex, supramarginal gyrus and precuneus, including hemisphere-specific activation that is lateralized in the same hemisphere, regardless of right- or left-sided paresis. We propose that these regions are candidates for an interface between psychological mechanisms and disturbed higher-order motor control. Our study presents an integrative neurophysiological view of the mechanisms that contribute to the etiology of this puzzling psychological disorder, which can be further investigated with other types of conversion symptoms.

Does neuroimaging of suggestion elucidate hypnotic trance?

Contemporary studies in the cognitive neuroscience of attention and suggestion shed new light on the underlying neural mechanisms that operationalize these effects. Without adhering to important caveats inherent to imaging of the living human brain, however, findings from brain imaging studies may enthrall more than explain. Scholars, practitioners, professionals, and consumers must realize that the influence words exert on focal brain activity is measurable but that these measurements are often difficult to interpret. While recent brain imaging research increasingly incorporates variations of suggestion and hypnosis, correlating overarching hypnotic experiences with specific brain substrates remains tenuous. This article elucidates the mounting role of cognitive neuroscience, including the relative merits and intrinsic limitations of neuroimaging, in better contextualizing trance-like concepts.

Review of neuroimaging studies related to pain modulation

Background and purpose: A noxious stimulus does not necessarily cause pain. Nociceptive signals arising from a noxious stimulus are subject to modulation via endogenous inhibitory and facilitatory mechanisms as they travel from the periphery to the dorsal horn or brainstem and on to higher brain sites. Research on the neural structures underlying endogenous pain modulation has largely been restricted to animal research due to the invasiveness of such studies (e.g., spinal cord transection, brain lesioning, brain site stimulation). Neuroimaging techniques (e.g., magnetoencephalography (MEG), positron emission tomography (PET) and functional magnetic resonance imaging (fMRI)) provide non-invasive means to study neural structures in humans. The aim is to provide a narrative review of neuroimaging studies related to human pain control mechanisms.

Methods: The approach taken is to summarise specific pain modulation mechanisms within the somatosensory (diffuse noxious inhibitory controls, acupuncture, movement), affective (depression, anxiety, catastrophizing, stress) and cognitive (anticipation/placebo, attention/distraction, hypnosis)domains with emphasis on the contribution of neuroimaging studies.

Results and conclusions: Findings from imaging studies are complex reflecting activation or deactivation in numerous brain areas. Despite this, neuroimaging techniques have clarified supraspinal sites involved in a number of pain control mechanisms. The periaqueductal grey (PAG) is one area that has consistently been shown to be activated across the majority of pain mechanisms. Activity in the rostral ventromedial medulla known to relay descending modulation from the PAG, has also been observed both during acupuncture analgesia and anxiety-induced hyperalgesia. Other brain areas that appear to be involved in a number of mechanisms are the anterior cingulate cortex, prefrontal cortex, orbitofrontal cortex and nucleus accumbens, but their exact role is less clear.

Implications: Neuroimaging studies have provided essential information about the pain modulatory pathways under normal conditions, but much is still to be determined. Understanding the mechanisms of pain control is important for understanding the mechanisms that contribute to failed pain control in chronic pain. Applying fMRI outside the brain, such as in the trigeminal nucleus caudalis of the spinotrigeminal pathway and in the dorsal horn of the spinal cord, and coupling brain activity with activity at these sites may help improve our understanding of the function of brain sites and shed light on functional connectivity in the pain pathway.

© 2011 Scandinavian Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Hypnosis for functional abdominal pain

Chronic abdominal pain is a common pediatric condition affecting 20% of the pediatric population worldwide. Most children with this disorder are found to have no specific organic etiology and are given the diagnosis of functional abdominal pain. Well-designed clinical trials have found hypnotherapy and guided imagery to be the most efficacious treatments for this condition. Hypnotic techniques used for other somatic symptoms are easily adaptable for use with functional abdominal pain. The author discusses 2 contrasting hypnotic approaches to functional abdominal pain and provides implications for further research. These approaches may provide new insights into this common and complex disorder.

Analysis of electrophysiological state patterns and changes during hypnosis induction

Hypnosis can be seen as a guided induction of various states of consciousness. This article details a time-series analysis that visualized the electrophysiological state changes during a session as a correlate to the instructions. Sixty-four channels of EEG and peripheral physiological measures were recorded in 1 highly susceptible subject. Significant state changes occurred synchronously with specific induction instructions. Some patterns could be physiologically explained, such as sensorimotor desynchronization over the right hemispheric hand area during left arm levitation. There was a highly significant increase in broadband activity during the stepwise trance induction that may point to a deep hypnotic state. This study provides illustrated proof for the detectability of physiological state changes as correlates to different states of awareness, consciousness, or cognition during hypnosis.

Hypnotic modulation of resting state fMRI default mode and extrinsic network connectivity

Resting state fMRI (functional magnetic resonance imaging) acquisitions are characterized by low-frequency spontaneous activity in a default mode network (encompassing medial brain areas and linked to self-related processes) and an anticorrelated "extrinsic" system (encompassing lateral frontoparietal areas and modulated via external sensory stimulation). In order to better determine the functional contribution of these networks to conscious awareness, we here sought to transiently modulate their relationship by means of hypnosis. We used independent component analysis (ICA) on resting state fMRI acquisitions during normal wakefulness, under hypnotic state, and during a control condition of autobiographical mental imagery. As compared to mental imagery, hypnosis-induced modulation of resting state fMRI networks resulted in a reduced "extrinsic" lateral frontoparietal cortical connectivity, possibly reflecting a decreased sensory awareness. The default mode network showed an increased connectivity in bilateral angular and middle frontal gyri, whereas its posterior midline and parahippocampal structures decreased their connectivity during hypnosis, supposedly related to an altered "self" awareness and posthypnotic amnesia. In our view, fMRI resting state studies of physiological (e.g., sleep or hypnosis), pharmacological (e.g., sedation or anesthesia), and pathological modulation (e.g., coma or related states) of "intrinsic" default mode and anticorrelated "extrinsic" sensory networks, and their interaction with other cerebral networks, will further improve our understanding of the neural correlates of subjective awareness.

[Ambulatory Essure implant placement sterilization procedure for women: prospective study comparing general anesthesia versus hypnosis combined with sedation]

OBJECTIVE

implant placement Essure, sterilization procedure for women, were performed under hypnosedation (HYP) and compared to the operative anxiety and analgesia of 12 patients operated-on under general anesthesia (GA).

STUDY DESIGN

prospective and comparative group study.

PATIENTS AND METHODS

two groups of twelve patients were matched and compared based on the choice of anesthetic technique: hypnotics (HYP) with possible additional sedation by propofol and remifentanil or GA involving propofol, sevoflurane and remifentanil. The assessment of anxiety and pain based on a visual analogy scale (0-10) and use of analgesics were studied in the recovery room and at discharge of hospital. The statistical analysis relies on nonparametric tests for paired data (Wilcoxon test).

RESULTS

all patients were operated. The two groups are statistically comparable. The preoperative anxiety before premedication is lower in the HYP group (p<0.05). No conversion to general anaesthesia is necessary in the HYP group, but five patients were using sedatives drugs but doses are very low compared to general anaesthesia. The analgesic consumption was equivalent in both groups.

CONCLUSION

we conclude that hypnosedation is a valuable alternative to traditional anesthetic techniques for ambulatory Essure implant. The use of hypnotic tool is an interesting alternative for the management of patients during invasive medical procedures or surgical, providing psychological benefits to the patient.

A prefrontal non-opioid mechanism in placebo analgesia

Behavioral studies have suggested that placebo analgesia is partly mediated by the endogenous opioid system. Expanding on these results we have shown that the opioid-receptor-rich rostral anterior cingulate cortex (rACC) is activated in both placebo and opioid analgesia. However, there are also differences between the two treatments. While opioids have direct pharmacological effects, acting on the descending pain inhibitory system, placebo analgesia depends on neocortical top-down mechanisms. An important difference may be that expectations are met to a lesser extent in placebo treatment as compared with a specific treatment, yielding a larger error signal. As these processes previously have been shown to influence other types of perceptual experiences, we hypothesized that they also may drive placebo analgesia. Imaging studies suggest that lateral orbitofrontal cortex (lObfc) and ventrolateral prefrontal cortex (vlPFC) are involved in processing expectation and error signals. We re-analyzed two independent functional imaging experiments related to placebo analgesia and emotional placebo to probe for a differential processing in these regions during placebo treatment vs. opioid treatment and to test if this activity is associated with the placebo response. In the first dataset lObfc and vlPFC showed an enhanced activation in placebo analgesia vs. opioid analgesia. Furthermore, the rACC activity co-varied with the prefrontal regions in the placebo condition specifically. A similar correlation between rACC and vlPFC was reproduced in another dataset involving emotional placebo and correlated with the degree of the placebo effect. Our results thus support that placebo is different from specific treatment with a prefrontal top-down influence on rACC.

The effect of opioid receptor blockade on the neural processing of thermal stimuli

The endogenous opioid system represents one of the principal systems in the modulation of pain. This has been demonstrated in studies of placebo analgesia and stress-induced analgesia, where anti-nociceptive activity triggered by pain itself or by cognitive states is blocked by opioid antagonists. The aim of this study was to characterize the effect of opioid receptor blockade on the physiological processing of painful thermal stimulation in the absence of cognitive manipulation. We therefore measured BOLD (blood oxygen level dependent) signal responses and intensity ratings to non-painful and painful thermal stimuli in a double-blind, cross-over design using the opioid receptor antagonist naloxone. On the behavioral level, we observed an increase in intensity ratings under naloxone due mainly to a difference in the non-painful stimuli. On the neural level, painful thermal stimulation was associated with a negative BOLD signal within the pregenual anterior cingulate cortex, and this deactivation was abolished by naloxone.

Top-down and bottom-up mechanisms in mind-body medicine: development of an integrative framework for psychophysiological research

It has become increasingly evident that bidirectional ("top-down and bottom-up") interactions between the brain and peripheral tissues, including the cardiovascular and immune systems, contribute to both mental and physical health. Therapies directed toward addressing functional links between mind/brain and body may be particularly effective in treating the range of symptoms associated with many chronic diseases. In this paper, we describe the basic components of an integrative psychophysiological framework for research aimed at elucidating the underlying substrates of mind-body therapies. This framework recognizes the multiple levels of the neuraxis at which mind-body interactions occur. We emphasize the role of specific fronto-temporal cortical regions in the representation and control of adverse symptoms, which interact reciprocally with subcortical structures involved in bodily homeostasis and responses to stress. Bidirectional autonomic and neuroendocrine pathways transmit information between the central nervous system and the periphery and facilitate the expression of affective, autonomic, hormonal, and immune responses. We propose that heart rate variability (HRV) and markers of inflammation are important currently available indices of central-peripheral integration and homeostasis within this homeostatic network. Finally, we review current neuroimaging and psychophysiological research from diverse areas of mind-body medicine that supports the framework as a basis for future research on the specific biobehavioral mechanisms of mind-body therapies.

Effects of methylphenidate on cerebral glucose metabolism in patients with impaired consciousness after acquired brain injury

OBJECTIVES

To evaluate the effects of methylphenidate on cerebral glucose metabolism in patients with impaired consciousness after acquired brain injury.

METHODS

Fourteen patients with impaired consciousness after acquired brain injury were enrolled in our study. We evaluated the level of consciousness with the Glasgow Coma Scale upon initial evaluation and at the 6-week follow-up after methylphenidate medication (0.3 mg/kg per day, which was administered twice daily). Positron emission tomography was performed before and after 6 weeks of medication, and the effects of methylphenidate on cerebral glucose metabolism were analyzed using statistical parametric mapping.

RESULTS

The statistical parametric mapping analysis indicated that significant increases of the cerebral glucose metabolism after methylphenidate therapy, compared with the initial positron emission tomographic image, were most evident in the left precuneus, the right posterior cingulated and the right retrosplenial cortices, and the right inferior parietal cortex (P < 0.001). In addition, cerebral glucose metabolism was significantly increased in the right precuneus, the right superior and middle temporal gyri, and bilateral middle occipital gyri (P < 0.005). In the correlation analysis, improvement of the Glasgow Coma Scale scores after methylphenidate medication was significantly associated with increased cerebral glucose metabolism in the bilateral precuneus, the bilateral middle occipital gyri, and right middle frontal gyrus.

CONCLUSIONS

Our findings suggest that the posteromedial parietal cortex, which is part of the neural network for consciousness, may be the relevant structure for the pharmacological response to methylphenidate treatment in patients with impaired consciousness after acquired brain injury.

Higher cortical modulation of pain perception in the human brain: Psychological determinant

Pain perception and its genesis in the human brain have been reviewed recently. In the current article, the reports on pain modulation in the human brain were reviewed from higher cortical regulation, i.e. top-down effect, particularly studied in psychological determinants. Pain modulation can be examined by gene therapy, physical modulation, pharmacological modulation, psychological modulation, and pathophysiological modulation. In psychological modulation, this article examined (a) willed determination, (b) distraction, (c) placebo, (d) hypnosis, (e) meditation, (f) qi-gong, (g) belief, and (h) emotions, respectively, in the brain function for pain modulation. In each, the operational definition, cortical processing, neuroimaging, and pain modulation were systematically deliberated. However, not all studies had featured the brain modulation processing but rather demonstrated potential effects on human pain. In our own studies on the emotional modulation on human pain, we observed that emotions could be induced from music melodies or pictures perception for reduction of tonic human pain, mainly in potentiation of the posterior alpha EEG fields, likely resulted from underneath activities of precuneous in regulation of consciousness, including pain perception. To sum, higher brain functions become the leading edge research in all sciences. How to solve the information bit of thinking and feeling in the brain can be the greatest challenge of human intelligence. Application of higher cortical modulation of human pain and suffering can lead to the progress of social humanity and civilization.

Cerebral and cerebrospinal processes underlying counterirritation analgesia

Pain is a complex experience involving extensive interactions between brain and spinal cord processes. Various interventions that modulate pain, such as the application of a competing noxious stimulus (counterirritation), are thought to involve cerebrospinal regulation through diffuse noxious inhibitory controls (DNICs). However, no study has yet examined the relation between brain and spinal cord activity during counterirritation analgesia in humans. This fMRI study investigates brain responses to phasic painful electrical stimulation administered to the sural nerve to evoke a spinal nociceptive response (RIII reflex) before, during and after counterirritation induced by the immersion of the left contralateral foot in cold water. Responses are compared with a control condition without counterirritation. As expected, counterirritation produced robust pain inhibition with residual analgesia persisting during the recovery period. In contrast, RIII reflex amplitude was significantly decreased by counterirritation only in a subset of subjects. Modulatory effects of counterirritation on pain perception and spinal nociception were paralleled by decreased shock-evoked activity in pain-related areas. Individual changes in shock-evoked brain activity were specifically related to analgesia in primary somatosensory cortex (SI), anterior cingulate cortex and amygdala, and to RIII modulation in supplementary motor area and orbitofrontal cortex (OFC). Moreover, sustained activation induced by the counterirritation stimulus in the OFC predicted shock-pain decrease while sustained activity in SI and the periaqueductal gray matter predicted RIII modulation. These results provide evidence for the implication of at least two partly separable neural mechanisms underlying the effects of counterirritation on pain and spinal nociception in humans.

Strength of prefrontal activation predicts intensity of suggestion-induced pain

Suggestion, a powerful factor in everyday social interaction, is most effective during hypnosis. Subjective evaluations and brain-imaging findings converge to propose that hypnotic suggestion strongly modulates sensory processing. To reveal the brain regions that mediate such a modulation, we analyzed data from a functional-magnetic-resonance-imaging study on hypnotic-suggestion-induced pain on 14 suggestible subjects. Activation strengths in the right dorsolateral prefrontal cortex (DLPFC) during initiation of suggestion for pain correlated positively with the subjective intensity of the subsequent suggestion-induced pain, as well as with the strengths of the maximum pain-related activation in the in the secondary somatosensory (SII) cortex. Furthermore, activation of the insula and the anterior cingulate cortex predicted the pain-related SII activation. The right DLPFC, as an area important for executive functions, likely contributes to functional modulation in the modality-specific target areas of given suggestions.

Hypnotic induction decreases anterior default mode activity

The 'default mode' network refers to cortical areas that are active in the absence of goal-directed activity. In previous studies, decreased activity in the 'default mode' has always been associated with increased activation in task-relevant areas. We show that the induction of hypnosis can reduce anterior default mode activity during rest without increasing activity in other cortical regions. We assessed brain activation patterns of high and low suggestible people while resting in the fMRI scanner and while engaged in visual tasks, in and out of hypnosis. High suggestible participants in hypnosis showed decreased brain activity in the anterior parts of the default mode circuit. In low suggestible people, hypnotic induction produced no detectable changes in these regions, but instead deactivated areas involved in alertness. The findings indicate that hypnotic induction creates a distinctive and unique pattern of brain activation in highly suggestible subjects.

The multiple dimensions of dyspnea: review and hypotheses

Although dyspnea is a common and troubling symptom, our understanding of the neurophysiology of dyspnea is woefully incomplete. Most measurements of dyspnea treat it as a single entity. Although the multidimensional dyspnea concept has been mentioned for many decades, only recently has the concept been the subject of experimental tests. Emerging evidence has begun to favor the hypothesis that dyspnea comprises multiple dimensions or components that can be measured as different entities. Most recently, studies have begun to show that there is a separable 'affective dimension' (i.e. unpleasantness and emotional impact). Understanding of the multidimensional measurement of pain is far in advance of dyspnea, and has enabled progress in the neurophysiology of pain, including identification of separate neural structures subserving various elements of pain perception. We propose here a multidimensional model of dyspnea based on a state-of-the-art pain model, and review existing evidence in the light of this model.

Pain and non-pain processing during hypnosis: a thulium-YAG event-related fMRI study

The neural mechanisms underlying the antinociceptive effects of hypnosis still remain unclear. Using a parametric single-trial thulium-YAG laser fMRI paradigm, we assessed changes in brain activation and connectivity related to the hypnotic state as compared to normal wakefulness in 13 healthy volunteers. Behaviorally, a difference in subjective ratings was found between normal wakefulness and hypnotic state for both non-painful and painful intensity-matched stimuli applied to the left hand. In normal wakefulness, non-painful range stimuli activated brainstem, contralateral primary somatosensory (S1) and bilateral insular cortices. Painful stimuli activated additional areas encompassing thalamus, bilateral striatum, anterior cingulate (ACC), premotor and dorsolateral prefrontal cortices. In hypnosis, intensity-matched stimuli in both the non-painful and painful range failed to elicit any cerebral activation. The interaction analysis identified that contralateral thalamus, bilateral striatum and ACC activated more in normal wakefulness compared to hypnosis during painful versus non-painful stimulation. Finally, we demonstrated hypnosis-related increases in functional connectivity between S1 and distant anterior insular and prefrontal cortices, possibly reflecting top-down modulation.

Perception and suppression of thermally induced pain: a fMRI study

Two neuroimaging studies using functional magnetic resonance imaging (fMRI) and thermally induced pain are presented. Fifteen healthy right-handed subjects were imaged while they had to discern different levels of thermal stimuli in the first study and while they disengaged from the feeling of pain during constant stimulation in the second study. In the first experiment, during painful phasic stimuli, right-sided anterior insular activation as well as bilateral posterior insular activation could be shown regardless of stimulation side, as well as right-sided activation of sensory association areas in the superior parietal lobule. Also, activation of the ipsilateral sensorimotor cortex could be shown. In the second experiment, all subjects succeeded in suppressing the feeling of pain during previously painful levels of stimulation. During the early part of the tonic painful stimulation, bilateral activation of caudate head and dorsolateral prefrontal cortex (DLPFC) as well as insular cortex and dorsal anterior cingulated cortex (dACC) was observed. During the late part of the tonic painful stimulation, anterior insular activation as well as dACC and bilateral prefrontal cortical activation could be shown. Taken together, the activation of PFC and caudate nucleus hints at an important role in the initiation (caudate) and maintenance (PFC) of suppression of the feeling of pain. No ipsilateral sensorimotor activation could be shown in the second experiment. The possible import of unwanted sensorimotor activation due to the simultaneous rating process in the first experiment is discussed.

EEG correlates of virtual reality hypnosis

The study investigated hypnosis-related electroencephalographic (EEG) coherence and power spectra changes in high and low hypnotizables (Stanford Hypnotic Clinical Scale) induced by a virtual reality hypnosis (VRH) induction system. In this study, the EEG from 17 participants (Mean age = 21.35, SD = 1.58) were compared based on their hypnotizability score. The EEG recording associated with a 2-minute, eyes-closed baseline state was compared to the EEG during a hypnosis-related state. This novel induction system was able to produce EEG findings consistent with previous hypnosis literature. Interactions of significance were found with EEG beta coherence. The high susceptibility group (n = 7) showed decreased coherence, while the low susceptibility group (n = 10) demonstrated an increase in coherence between medial frontal and lateral left prefrontal sites. Methodological and efficacy issues are discussed.