Chronic low-back pain modulation is enhanced by hypnotic analgesic suggestion by recruiting an emotional network: a PET imaging study

Neuroscientific results of experimental studies on the control of acute pain with hypnosis and suggested analgesia

This narrative review summarizes a representative collection of electrophysiological and imaging studies on the neural processes and brain sources underlying hypnotic trance and the effects of hypnotic suggestions on the processing of experimentally induced painful events. It complements several reviews on the effect of hypnosis on brain processes and structures of chronic pain processing. Based on a summary of previous findings on the neuronal processing of experimentally applied pain stimuli and their effects on neuronal brain structures in healthy subjects, three neurophysiological methods are then presented that examine which of these neuronal processes and structures get demonstrably altered by hypnosis and can thus be interpreted as neuronal signatures of the effect of analgesic suggestions: (A) On a more global neuronal level, these are electrical processes of the brain that can be recorded from the cranial surface of the brain with magnetoencephalography (MEG) and electroencephalography (EEG). (B) On a second level, so-called evoked (EPs) or event-related potentials (ERPs) are discussed, which represent a subset of the brain electrical parameters of the EEG. (C) Thirdly, imaging procedures are summarized that focus on brain structures involved in the processing of pain states and belong to the main imaging procedures of magnetic resonance imaging (MRI/fMRI) and positron emission tomography (PET). Finally, these different approaches are summarized in a discussion, and some research and methodological suggestions are made as to how this research could be improved in the future.

Neural functional correlates of hypnosis and hypnoanalgesia: Role of the cingulate cortex

Hypnosis is a hetero-induced or self-induced altered state of consciousness that involves focused attention and reduced peripheral awareness. It is determined by response to suggestions and can be used in the management of various clinical conditions. Nowadays there is growing attention to the neurobiological correlates of hypnosis because of its future clinical applications. The greater attention is due to the wide range of applications that might stem from its knowledge. Functional neuroimaging studies show that hypnosis affects attention by modulating the activation of the anterior cingulate cortex and other brain areas, modifying the conflict monitoring and cognitive control. During hypnoanalgesia, several changes in brain functions occur in all the areas of the pain network, and other brain areas. Among these, the anterior cingulate cortex is significantly involved in modulating the activity of pain circuits under hypnosis, both in the affective, sensory-cognitive, and behavioral aspects. The study of the functionality of the cingulate cortices, mainly the anterior and medial portions, appears to be crucial for better understanding the hypnotic phenomena, related to both the neurocognitive and somatosensory aspects.

Neurophysiology of hypnosis in chronic pain: A review of recent literature

Chronic pain is a complex phenomenon which includes biological, psychological, and socio-professional factors that undermine patients' everyday life. Currently, only few patients significantly benefit from pharmacological treatments and many have to stop them because of negative side effects. Moreover, no medication or treatment addresses all aspects of chronic pain at once (i.e., sensations, emotions, behaviors, and cognitions), positioning chronic pain as an important public health issue and thus contributing to high health-care costs. Consequently, patients and health-care providers are increasingly turning to complementary non-pharmacological techniques such as hypnosis. Clinical research has demonstrated a decrease of pain perception, pain interference, depression and anxiety, and an increase in global quality of life when patients with chronic pain have benefited from hypnosis learning. Neuroimaging studies offer a possible explanation of these results by focusing on neural processes of pain modulation in chronic pain patients' brain. Studies conducted with chronic pain patients showed a modulation of pain matrix activity during hypnosis with a specific involvement of the anterior cingulate cortex (related to emotional and cognitive processing of pain). Therefore, hypnosis seems to act upon regions underlying emotion and cognition, with an influence on pain perception and emotional regulation. In this review, we propose to carry out a review of the recent literature on hypnosis in chronic pain management. A better understanding of the beneficial effects of hypnosis on chronic pain and its neurophysiology should enable more systematic use of this technique in the management of this complex health problem.

Hypnosis As A Therapy for Chronic Lower Back Pain

PURPOSE OF REVIEW

Chronic lower back pain is a crippling condition for the individual and a significant burden on society. It is notoriously challenging to manage despite access to invasive interventions. Understanding hypnosis as a powerful therapeutic adjunct to this condition allows holistic treatment of patients in distress.

RECENT FINDINGS

In addition to classic etiologies of chronic lower back pain, hypnosis has proven to be beneficial in chronic back pain caused by pregnancy, diabetic and HIV neuropathy. Combination of hypnosis with other mind-body techniques such as olfactory stimulation, music therapy and patient education offers further promise to this treatment modality. Our review provides a run-through of the fundamental mechanisms of hypnosis in moderating chronic back pain, its quantifiable benefits, its novel areas of use and its potentials in the future based on the most recent and relevant peer-reviewed literature in order to guide clinicians to better deploy this valuable resource.

Brain Imaging Biomarkers for Chronic Pain

The prevalence of chronic pain has reached epidemic levels. In addition to personal suffering chronic pain is associated with psychiatric and medical co-morbidities, notably substance misuse, and a huge a societal cost amounting to hundreds of billions of dollars annually in medical cost, lost wages, and productivity. Chronic pain does not have a cure or quantitative diagnostic or prognostic tools. In this manuscript we provide evidence that this situation is about to change. We first start by summarizing our current understanding of the role of the brain in the pathogenesis of chronic pain. We particularly focus on the concept of learning in the emergence of chronic pain, and the implication of the limbic brain circuitry and dopaminergic signaling, which underly emotional learning and decision making, in this process. Next, we summarize data from our labs and from other groups on the latest brain imaging findings in different chronic pain conditions focusing on results with significant potential for translation into clinical applications. The gaps in the study of chronic pain and brain imaging are highlighted in throughout the overview. Finally, we conclude by discussing the costs and benefits of using brain biomarkers of chronic pain and compare to other potential markers.

The Effect of Hypnosis on the Intensity of Pain and Anxiety in Cancer Patients: A Systematic Review of Controlled Experimental Trials

BACKGROUND

Pain is a common symptom in cancer patients. Hypnosis is considered one of the most recognized non-pharmacological techniques in pain management. In oncology, this technique can be used as a complementary treatment to reduce the level of pain and anxiety. The objective of this study is to systematically review and evaluate controlled clinical trials (CCTs) examining the effect of hypnosis on the intensity of pain, and anxiety in cancer patients.

METHODS

A systematic review was conducted according to the recommendations of the "Preferred reporting items for systematic reviews and meta-analyses" (PRISMA). The Cochrane systematic review database, the abstract databases, Scopus, PubMed, Google Scholar, and Cochrane Library have been systematically reviewed from 2005 to 2018.

RESULTS

Eleven CCT with a total of 1182 participants met the inclusion criteria and were included in this review. The participants were mainly women (n = 968). Their average age alternates between 48 and 58 years. Perceived pain was measured primarily by visual analog scale (VAS)/numerical pain rating scale (NPRS), which showed that anxiety was measured by Hospital Anxiety and Depression scale (HADS). Hypnosis-related anxiety and pain decreased significantly with respect to usual treatment.

CONCLUSIONS

Evidence suggests promising results of hypnosis on the management of pain, and anxiety levels in the vast majority of cancer patients. Therefore, because of the exploratory design and high risk of bias, the effectiveness of hypnosis or hypnotherapy in reducing pain and anxiety levels remains unclear. There is a need for more rigorous randomized controlled trials (RCTs).

Feasibility and acceptability of hypnosis-derived communication administered by trained nurses to improve patient well-being during outpatient chemotherapy: a pilot-controlled trial

Purpose

This pilot-controlled trial aimed to examine the feasibility and acceptability of hypnosis-derived communication (HC) administered by trained nurses during outpatient chemotherapy to optimize symptom management and emotional support — two important aspects of patient well-being in oncology.

Methods

The trial was conducted in two outpatient oncology units: (1) intervention site (usual care with HC), and (2) control site (usual care). Nurses at the intervention site were invited to take part in an 8-h training in HC. Participants’ self-ratings of symptoms and emotional support were gathered at predetermined time points during three consecutive outpatient visits using the Edmonton Symptom Assessment Scale and the Emotional Support Scale.

Results

Forty-nine patients (24 in the intervention group, 25 in the control group) with different cancer types/stages were recruited over a period of 3 weeks and completed the study. All nurses (N = 10) at the intervention site volunteered to complete the training and were able to include HC into their chemotherapy protocols (about ± 5 min/intervention). Compared to usual care, patients exposed to HC showed a significant reduction in physical symptoms during chemotherapy. In contrast, perception of emotional support did not show any significant effect of the intervention. Participants exposed to HC report that the intervention helped them relax and connect on a more personal level with the nurse during chemotherapy infusion.

Conclusions

Our results suggest that HC is feasible, acceptable, and beneficial for symptom management during outpatient chemotherapy. While future studies are needed, hypnosis techniques could facilitate meaningful contacts between cancer patients and clinicians in oncology.

Trial registration

Clinical Trial Identifier: NCT04173195, first posted on November 19, 2019

Supplementary Information

The online version contains supplementary material available at 10.1007/s00520-021-06481-6.

Nurse's knowledge and perceptions on communicative hypnosis: an observational study

Background and aim of the study.

Much evidence shows that hypnotic communication can have a pain-relieving effect and reduce complications such as anxiety, insomnia and depression. Whenever this technique was applied, the use of pharmaceuticals was reduced, there were fewer side effects, shorter hospitalization times frames and lower treatment costs. The aim of this study is to evaluate the knowledge and perceptions of nurses about hypnotic communication and the causes for which this technique is not frequently used. A secondary objective pointed to measuring the effectiveness of an educational event on hypnosis.

Method.

The evaluation was done by directly administering an anonymous and voluntary survey created ad hoc, in a pre-test and post-test modality, to nurses subscribed to a four-hour formative event on hypnotic communication organized in 2019 by the Nursing Order, Province of Ravenna.

Results.

78 nurses (85.7%) participated in the study. The analysis of the pre-test results shows a gap of knowledge regarding hypnotic communication. The variation of answers between the pre-test and post-test (T-Student) has shown a radical difference in knowledge (95%-100% correct answers). The main causes were found regarding the lack of use for hypnotic communication: stereotypes and prejudices related to this technique and insufficient university education.

Conclusions.

The implementation of this technique, effective and efficient under various aspects, requires a preliminary creation of culture regarding this theme, capable of surpassing the stereotypes and resistances brought by a lack of theoretical elements.

Efficacy of a combination of hypnosis and transcutaneous electrical nerve stimulation for chronic non-cancer pain: A randomized controlled trial

BACKGROUND

Chronic non-cancer pain, which persists for at least three months, seriously affects quality of life. Chronic non-cancer pain patients are usually managed by a multidisciplinary team using pharmacological and non-pharmacological strategies. Nurses perform transcutaneous electrical nerve stimulation (TENS) and hypnosis, which are widely used in France for the treatment of chronic pain in pain departments.

OBJECTIVE

To assess pain relief at three months, comparing a simultaneous combination of hypnosis and TENS (intervention) with TENS alone (control).

DESIGN

Randomized controlled trial.

METHODS

Patients aged 18-80 years, suffering from chronic peripheral neuropathic and/or nociceptive non-cancer pain were included (September 2013 to May 2017) and followed for six months. The primary outcome was the pain intensity difference (by visual analog scale score) between month 3 and baseline. The secondary outcomes, assessed at months 3 and 6, were SF36 score, analgesics consumption and number of TENS sessions performed at home (last seven days).

RESULTS

Seventy-two patients were included, suffering from a combination of chronic non-cancer nociceptive and neuropathic pain, with a mean pain intensity of about sixty out of a hundred. The results show an important pain reduction (forty percent) in both groups at 3 months. No significant difference was observed between the control and intervention groups. Similarly, SF36 score, change in analgesic intake and patient compliance did not differ significantly between groups.

CONCLUSIONS

This is the first randomized controlled study showing a decrease of pain intensity and a high level of compliance with transcutaneous electrical nerve stimulation alone or associated to hypnosis. The combination does not seem to be more efficient than transcutaneous electrical nerve stimulation alone. Chronic non-cancer pain remains a major issue and a substantial proportion of patients do not appear to benefit from interventions.

IMPACT

This study increases our understanding of the combination of two non-pharmacological methods in chronic non-cancer pain patients. The combination of the two non-pharmacological strategies did not appear to be more efficient than one alone. Further research on non-pharmacological treatments targeting to patient's characteristics are needed to find appropriate strategies in patients with complex multidimensional pain conditions. Clinical Trial Number: NCT01944150 (Sept. 17, 2013).

Mind-Body Interventions for Rehabilitation Medicine: Promoting Wellness, Healing, and Coping with Adversity

Physical medicine providers work to cure organic aspects of disease while simultaneously enhancing quality of life and well-being. Mind-body interventions are evidence-based, cost-effective approaches to serve these aims. This article enhances provider knowledge and acceptance of the most effective and prevalent mind-body modalities: meditation, guided imagery, clinical hypnosis, and biofeedback. The scientific evidence is strongest for mind-body applications for chronic pain, primary headache, cardiac rehabilitation, and cancer rehabilitation, with preliminary evidence for traumatic brain injury and cerebrovascular events. Mind-body interventions are well-tolerated by patients and should be considered part of standard care in physical medicine and rehabilitation settings.

Association between Anterior Cingulate Neurochemical Concentration and Individual Differences in Hypnotizability

Hypnosis is the oldest form of Western psychotherapy and a powerful evidence-based treatment for numerous disorders. Hypnotizability is variable between individuals; however, it is a stable trait throughout adulthood, suggesting that neurophysiological factors may underlie hypnotic responsiveness. One brain region of particular interest in functional neuroimaging studies of hypnotizability is the anterior cingulate cortex (ACC). Here, we examined the relationships between the neurochemicals, GABA, and glutamate, in the ACC and hypnotizability in healthy individuals. Participants underwent a magnetic resonance imaging (MRI) session, whereby T1-weighted anatomical and MEGA-PRESS spectroscopy scans were acquired. Voxel placement over the ACC was guided by a quantitative meta-analysis of functional neuroimaging studies of hypnosis. Hypnotizability was assessed using the Hypnotic Induction Profile (HIP), and self-report questionnaires to assess absorption (TAS), dissociation (DES), and negative affect were completed. ACC GABA concentration was positively associated with HIP scores such that the higher the GABA concentration, the more hypnotizable an individual. An exploratory analysis of questionnaire subscales revealed a negative relationship between glutamate and the absorption and imaginative involvement subscale of the DES. These results provide a putative neurobiological basis for individual differences in hypnotizability and can inform our understanding of treatment response to this growing psychotherapeutic tool.

Effect of an Online Hypnosis Intervention in Reducing Migraine Symptoms: A Randomized Controlled Trial

This study examined the development and effect of an online hypnosis program for the treatment of migraines. Forty-three participants were randomly assigned to a wait-list control or a treatment group. The treatment group received hypnosis mp3s developed for the study. Pain catastrophizing (PCS), headache disability (HDI), migraine frequency, duration, severity, and medication usage were measured. There was a 48% reduction in mean HDI score in the treatment group and 2% reduction in the control group. There was a 60% reduction in mean PCS score in the treatment group. There were no significant between-group differences in the proportion of subjects experiencing decreased frequency or severity of migraines. There was a significant between-group difference in the change in migraine duration. This study demonstrated that a hypnosis intervention delivered online was effective in reducing headache symptoms in migraine sufferers.

Investigation of the Effect of Hypnotic Anesthesia on Nerve Conduction Velocity (NCV)

Background

Hypnosis is a psychological method used for treatment of different types of disorders and illnesses. This technique is also used in surgical interventions. Many studies proved the efficacy of hypnosis in medical treatment. However, the mechanism of hypnosis is unclear for scientists. To find out if the peripheral nervous system has a role in hypnotic anesthesia, we aimed to investigate the effect of hypnotic anesthesia on nerve conduction velocity (NCV).

Methods

In this study, healthy volunteers with high hypnotizability entered the study. First, The NCV test was performed in both hands of participants and then they all underwent hypnosis. Hypnotic anesthesia was induced in the right hand of all subjects followed by painful stimuli in their hand by vascular clasping. Then, the NCV test was repeated in both hands again. Data were analyzed by SPSS version16.

Results

The group study consisted of 13 (65%) women and 7 (35%) men with their age ranging between 14 to 52 years. According to the results, the mean values of sensory latency, and NCV changed from 3.225 ms and 54.355 m/s before hypnotic anesthesia to 3.32 ms and 55.3 m/s after hypnotic anesthesia in right hand, respectively. Results showed that there was a significant difference between data before and after hypnotic induction (P < 0.001). The covariance test also indicated a significant difference between the data obtained from both hands (P < 0.001).

Conclusions

In contrast to our hypothesis, the NCV test showed an increase after the hypnotic anesthesia. However, increase in NCV did not lead to experience pain after the painful stimuli. It seems that central nervous system should be involved in this process.

Brodmann area 10: Collating, integrating and high level processing of nociception and pain

Multiple frontal cortical brain regions have emerged as being important in pain processing, whether it be integrative, sensory, cognitive, or emotional. One such region, Brodmann Area 10 (BA 10), is the largest frontal brain region that has been shown to be involved in a wide variety of functions including risk and decision making, odor evaluation, reward and conflict, pain, and working memory. BA 10, also known as the anterior prefrontal cortex, frontopolar prefrontal cortex or rostral prefrontal cortex, is comprised of at least two cytoarchitectonic sub-regions, medial and lateral. To date, the explicit role of BA 10 in the processing of pain hasn't been fully elucidated. In this paper, we first review the anatomical pathways and functional connectivity of BA 10. Numerous functional imaging studies of experimental or clinical pain have also reported brain activations and/or deactivations in BA 10 in response to painful events. The evidence suggests that BA 10 may play a critical role in the collation, integration and high-level processing of nociception and pain, but also reveals possible functional distinctions between the subregions of BA 10 in this process.

Oxytocin in hypothalamic supraoptic nucleus is transferred to the caudate nucleus to influence pain modulation

Oxytocin (OXT), which is synthesized and secreted in the hypothalamic supraoptic nucleus (SON), is the most important bioactive substance in SON regulating pain process. Our previous study has pointed that OXT in the caudate nucleus (CdN) plays a role in pain modulation. The communication was designed to investigate the source of OXT in the rat CdN during pain process using the methods of push-pull perfusion and radioimmunoassay. The results showed that (1) pain stimulation increased the OXT concentration in the CdN perfusion liquid; (2) SON cauterization inhibited the increase of OXT concentration in CdN perfusion liquid induced by the pain stimulation, which role in both sides of SON cauterization was stronger than that in one side of SON cauterization; and (3) SON microinjection of l-glutamate sodium, which excited the SON neurons, increased OXT concentration in the CdN perfusion liquid. The data suggested that OXT in the CdN was influenced by SON during pain process, i.e., OXT in the SON might be transferred to the CdN to influence pain modulation.

An Evaluation of the Effect of Hypnosis on Postoperative Analgesia following Laparoscopic Cholecystectomy

Little attention has been paid to the effectiveness of hypnosis in improving the results of surgery in Iran. One hundred and twenty patients scheduled for laparoscopic cholecystectomy were randomly divided into either control (standard care) or experimental (hypnosis) groups. Prior to surgery and again after surgery, abdominal pain, nausea, and vomiting were assessed. The results suggest that hypnosis could effectively reduce pain after laparoscopic cholecystectomy and significantly reduce hospitalization time.

[Relaxation and hypnosis in care]

Pain is multifactorial, requiring multi-dimensional treatment. The cross-disciplinary care provided in pain assessment and treatment centres offers patients a global treatment. As a complement to conventional treatment, the patient's care pathway may include psycho-corporal therapy with psychotherapeutic input.

Pain perception and hypnosis: findings from recent functional neuroimaging studies

Hypnosis modulates pain perception and tolerance by affecting cortical and subcortical activity in brain regions involved in these processes. By reviewing functional neuroimaging studies focusing on pain perception under hypnosis, the authors aimed to identify brain activation-deactivation patterns occurring in hypnosis-modulated pain conditions. Different changes in brain functionality occurred throughout all components of the pain network and other brain areas. The anterior cingulate cortex appears to be central in modulating pain circuitry activity under hypnosis. Most studies also showed that the neural functions of the prefrontal, insular, and somatosensory cortices are consistently modified during hypnosis-modulated pain conditions. Functional neuroimaging studies support the clinical use of hypnosis in the management of pain conditions.

Hypnosis and imaging of the living human brain

Over more than two decades, studies using imaging techniques of the living human brain have begun to explore the neural correlates of hypnosis. The collective findings provide a gripping, albeit preliminary, account of the underlying neurobiological mechanisms involved in hypnotic phenomena. While substantial advances lend support to different hypotheses pertaining to hypnotic modulation of attention, control, and monitoring processes, the complex interactions among the many mediating variables largely hinder our ability to isolate robust commonalities across studies. The present account presents a critical integrative synthesis of neuroimaging studies targeting hypnosis as a function of suggestion. Specifically, hypnotic induction without task-specific suggestion is examined, as well as suggestions concerning sensation and perception, memory, and ideomotor response. The importance of carefully designed experiments is highlighted to better tease apart the neural correlates that subserve hypnotic phenomena. Moreover, converging findings intimate that hypnotic suggestions seem to induce specific neural patterns. These observations propose that suggestions may have the ability to target focal brain networks. Drawing on evidence spanning several technological modalities, neuroimaging studies of hypnosis pave the road to a more scientific understanding of a dramatic, yet largely evasive, domain of human behavior.

Resting-state connectivity in the default mode network and insula during experimental low back pain

Functional magnetic resonance imaging studies have shown that the insular cortex has a significant role in pain identification and information integration, while the default mode network is associated with cognitive and memory-related aspects of pain perception. However, changes in the functional connectivity between the default mode network and insula during pain remain unclear. This study used 3.0 T functional magnetic resonance imaging scans in 12 healthy subjects aged 24.8 ± 3.3 years to compare the differences in the functional activity and connectivity of the insula and default mode network between the baseline and pain condition induced by intramuscular injection of hypertonic saline. Compared with the baseline, the insula was more functionally connected with the medial prefrontal and lateral temporal cortices, whereas there was lower connectivity with the posterior cingulate cortex, precuneus and inferior parietal lobule in the pain condition. In addition, compared with baseline, the anterior cingulate cortex exhibited greater connectivity with the posterior insula, but lower connectivity with the anterior insula, during the pain condition. These data indicate that experimental low back pain led to dysfunction in the connectivity between the insula and default mode network resulting from an impairment of the regions of the brain related to cognition and emotion, suggesting the importance of the interaction between these regions in pain processing.

Neurophysiology of hypnosis

We here review behavioral, neuroimaging and electrophysiological studies of hypnosis as a state, as well as hypnosis as a tool to modulate brain responses to painful stimulations. Studies have shown that hypnotic processes modify internal (self awareness) as well as external (environmental awareness) brain networks. Brain mechanisms underlying the modulation of pain perception under hypnotic conditions involve cortical as well as subcortical areas including anterior cingulate and prefrontal cortices, basal ganglia and thalami. Combined with local anesthesia and conscious sedation in patients undergoing surgery, hypnosis is associated with improved peri- and postoperative comfort of patients and surgeons. Finally, hypnosis can be considered as a useful analogue for simulating conversion and dissociation symptoms in healthy subjects, permitting better characterization of these challenging disorders by producing clinically similar experiences.

Neurophysiology of pain and hypnosis for chronic pain

In the past decade there has been a dramatic increase in (1) understanding the neurophysiological components of the pain experiences, (2) randomized clinical trials testing the efficacy of hypnotic treatments on chronic pain, and (3) laboratory research examining the effects of hypnosis on the neurophysiological processes implicated in pain. Work done in these areas has not only demonstrated the efficacy of hypnosis for treating chronic pain but is beginning to shed light on neurophysiological processes that may play a role in its effectiveness. This paper reviews a selection of published studies from these areas of research, focusing on recent findings that have the most potential to inform both clinical work and research in this area. The paper concludes with research and clinical recommendations for maximizing treatment efficacy based on the research findings that are available.

Hypnosis for management of fibromyalgia

This randomized, controlled trial contrasted the effects of 5 not-standardized sessions of hypnosis over 2 months in 59 women with fibromyalgia who were randomly assigned to treatment (n = 30) or a wait-list control group (n = 29). Patients in the treated group were encouraged to practice self-hypnosis. Fibromyalgia Impact Questionnaire (FIQ), MOS-Sleep Scale, Multidimensional Fatigue Inventory (MFI), Cognitive Strategy Questionnaire (CSQ), and Patient Global Impression of Change (PGIC) were administered at baseline, 3 months (M3), and 6 months (M6) after inclusion. Compared to the control, the hypnosis group reported better improvement on PGIC (p = .001 at M3, p = .01 at M6) and a significant improvement in sleep and CSQ dramatization subscale (both at M6).

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.

Oxytocin in the rat caudate nucleus influences pain modulation

Our previous studies have demonstrated that oxytocin (OXT) in the central nervous system plays a role in pain modulation. Many studies have found that caudate nucleus (CdN) enriches OXT and OXT receptors by the methods of historadioautograph and gene expression. The communication was designed to investigate OXT effect in the rat CdN on pain modulation. The results showed that (1) intra-CdN microinjection of OXT receptor antagonist, desGly-NH(2), d(CH(2))(5)[D-Tyr(2), Thr-sup-4]OVT decreased the pain threshold, whereas the local administration of OXT increased the pain threshold in a dose-dependent manner; (2) OXT receptor antagonist can attenuate the analgesic role induced intra-CdN administration of OXT; and (3) pain stimulation could increase OXT concentration in the CdN perfusion liquid. The data suggested that OXT in the CdN was involved in this pain process via OXT receptors.