Meditation experience predicts less negative appraisal of pain: electrophysiological evidence for the involvement of anticipatory neural responses

From Confound to Clinical Tool: Mindfulness and the Observer Effect in Research and Therapy

The observer effect (OE), the idea that observing a phenomenon changes it, has important implications across scientific disciplines involving measurement and observation. While often viewed as a confounding variable to control for, this paper argues that the OE should be seriously accounted for, explored, and systematically leveraged in research and clinical settings. Specifically, mindfulness practices that cultivate present-moment, nonjudgmental awareness are proposed as a platform to account for, explore, and intentionally harness the OE. In research contexts, mindfulness training may allow participants to provide more precise self-reports by minimizing reactive biases that perturb the observed phenomena. Empirical evidence suggests that mindfulness enhances interoceptive awareness and reduces automatic judgment, potentially increasing measurement sensitivity, specificity, and validity. Clinically, psychotherapies often aim to make unconscious patterns explicitly observable to the client, capitalizing on the transformative potential of observation. Mindfulness directly cultivates this capacity for meta-awareness, allowing individuals to decenter from rigid cognitive-emotional patterns fueling psychopathology. Rather than avoiding unpleasant experiences such as cravings or anxiety, mindfulness guides individuals to simply observe these phenomena, reducing identification and reactivity. Mindfulness practices may leverage components of the OE, facilitating lasting psychological change. To further study the OE, developing an OE index to code observer influence is proposed. Overall, this paper highlights the ubiquity of the OE and advocates developing methods to intentionally account for and apply observer influences across research and therapeutic contexts.

EEG oscillations reveal neuroplastic changes in pain processing associated with long-term meditation

The experience of pain is a combined product of bottom-up and top-down influences mediated by attentional and emotional factors. Meditation states and traits are characterized by enhanced attention/emotion regulation and expanded self-awareness that can be expected to modify pain processing. The main objective of the present study was to explore the effects of long-term meditation on neural mechanisms of pain processing. EEG pain-related oscillations (PROs) were analysed in highly experienced practitioners and novices during a non-meditative resting state with respect to (a) local frequency-specific and temporal synchronizing characteristics to reflect mainly bottom-up mechanisms, (b) spatial synchronizing patterns to reflect the neural communication of noxious information, (c) pre-stimulus oscillations to reflect top-down mechanisms during pain expectancy, and (d) the P3b component of the pain-related potential to compare the emotional/cognitive reappraisal of pain events by expert and novice meditators. Main results demonstrated that in experienced (long-term) meditators as compared to non-experienced (short-term) meditators (1) the temporal and spatial synchronizations of multispectral (from theta-alpha to gamma) PROs were substantially suppressed at primary and secondary somatosensory regions contra-lateral to pain stimulation within 200 ms after noxious stimulus; (2) pre-stimulus alpha activity was significantly increased at the same regions, which predicted the suppressed synchronization of PROs in long-term meditators; (3) the decrease of the P3b component was non-significant. These novel observations provide evidence that even when subjected to pain outside of meditation, experienced meditators exhibit a pro-active top-down inhibition of somatosensory areas resulting in suppressed processing and communication of sensory information at early stages of painful input. The emotional/cognitive appraisal of pain is reduced but remains preserved revealing a capacity of experienced meditators to dissociate pro-active and reactive top-down processes during pain control.

Neural regulation of pain anticipation is associated with mindful behavior change in patients with anxiety or depression: A pilot study

Behavior change often requires overcoming discomfort or difficult emotions. Emotional dysregulation associated with anxiety or depression may prevent behavior change initiation among people managing chronic illness. Mindfulness training may catalyze chronic disease self-management by reducing experiential avoidance of aversive experiences that act as barriers to change initiation. Using a fMRI evoked pain task, we examined the effects of 8 weeks of Mindfulness Training for Primary Care (MTPC) on brain response to the anticipation of a noxious event (i.e., pain) among patients with anxiety and/or depression. We modeled the association between post-MTPC changes in brain response to pain anticipation and post-MTPC Action Plan Initiation (API), a measure of successful initiation of health behavior change. Greater post-MTPC increase in response to pain anticipation in the dorsal medial prefrontal cortex (dmPFC) was associated with higher levels of API (r=0.77, p<0.001). This increase in dmPFC response correlated with post-MTPC self-reported increase in emotion regulation skills related to goal-directed behaviors (r=-0.52, p=0.002). This suggests that mindfulness training increases the capacity to maintain goal-directed behavior in the face of aversive experiences by strengthening neural mechanisms of emotion- and self-regulation supporting successful health behavior change initiation in patients struggling with anxiety and/or depression.

Mindfulness Meditation and Placebo Modulate Distinct Multivariate Neural Signatures to Reduce Pain

BACKGROUND

Rather than a passive reflection of nociception, pain is shaped by the interplay between one's experiences, current cognitive-affective states, and expectations. The placebo response, a paradoxical yet reliable phenomenon, is postulated to reduce pain by engaging mechanisms shared with active therapies. It has been assumed that mindfulness meditation, practiced by sustaining nonjudgmental awareness of arising sensory events, merely reflects mechanisms evoked by placebo. Recently, brain-based multivariate pattern analysis has been validated to successfully disentangle nociceptive-specific, negative affective, and placebo-based dimensions of the subjective pain experience.

METHODS

To determine whether mindfulness meditation engages distinct brain mechanisms from placebo and sham mindfulness to reduce pain, multivariate pattern analysis pain signatures were applied across 2 randomized clinical trials that employed overlapping psychophysical pain testing procedures (49 °C noxious heat; visual analog pain scales) and distinct functional magnetic resonance imaging techniques (blood oxygen level-dependent; perfusion based). After baseline pain testing, 115 healthy participants were randomized into a 4-session mindfulness meditation (n = 37), placebo-cream conditioning (n = 19), sham mindfulness meditation (n = 20), or book-listening control (n = 39) intervention. After each intervention, noxious heat was administered during functional magnetic resonance imaging and each manipulation.

RESULTS

A double dissociation in the multivariate pattern analysis signatures supporting pain regulation was revealed by mindfulness meditation compared with placebo cream. Mindfulness meditation produced significantly greater reductions in pain intensity and pain unpleasantness ratings and nociceptive-specific and negative affective pain signatures than placebo cream, sham mindfulness meditation, and control interventions. The placebo-cream group significantly lowered the placebo-based signature.

CONCLUSIONS

Mindfulness meditation and placebo engaged distinct and granular neural pain signatures to reduce pain.

Experience of compassion-based practice in mindfulness for health for individuals with persistent pain

Purpose of the Study

Research indicates that acquiring compassion is an integral part to positive outcomes to Mindfulness-based interventions (MBI), yet there is both theoretic and empirical literature suggesting that people with persistent pain are more likely to experience challenges and distress when engaging compassion-based practices. Mindfulness for Health is a standardised MBI for people with persistent pain and health conditions. This study sought to explore the positive, neutral and difficult experiences of compassion-based practice and meditation for participants in Mindfulness for Health to further understand implications and risks for participants of MBI's.

Method and Design

A qualitative design using Interpretative Phenomenological Analysis was applied to explore how participants understood of the experience of compassion-based practice and the meaning they gave to it. Eight participants who had completed the Mindfulness for Health from four separate groups were interviewed about their experience.

Results

Five master themes were identified 'turning away from self-with-pain', 'self-with-pain experienced as shameful', 'facilitating change', 'turning towards self-with-pain', and 'accepting self'. Participants identified both perceived positive changes and difficult emotional experiences during the meditation practice, which they related to the context of compassion in their past and present life.

Conclusions

Developing compassion is an important part of Mindfulness for Health, which is salient for participants as both a challenging and potentially valuable experience. Acquisition of mindfulness skills, supporting group dynamics and modelling compassion are understood as helpful in overcoming personal barriers and challenging experiences. Further research is needed to understand processes involved and explore the experience of non-completers.

Vigilance to Painful Laser Stimuli is Associated with Increased State Anxiety and Tense Arousal

Introduction

Pain is frequently accompanied by enhanced arousal and hypervigilance to painful sensations. Here, we describe our findings in an experimental vigilance task requiring healthy participants to indicate when randomly timed moderately painful stimuli occur in a long train of mildly painful stimuli.

Methods

During a continuous performance task with painful laser stimuli (CPTpain), 18 participants rated pain intensity, unpleasantness, and salience. We tested for a vigilance decrement over time using classical metrics including correct targets (hits), incorrectly identified non-targets (false alarms), hit reaction time, and false alarm reaction time. We measured state anxiety and tense arousal before and after the task.

Results

We found a vigilance decrement across four 12.5-minute blocks of painful laser stimuli in hits [F3,51=2.91; p=0.043; time block 1>block 4 (t=2.77; p=0.035)]. Both self-report state anxiety (tpaired,17=3.34; p=0.0039) and tense arousal (tpaired,17=3.20; p=0.0053) increased after the task. We found a vigilance decrement during our laser pain vigilance task consistent with vigilance decrements found in other stimulus modalities. Furthermore, state anxiety positively correlated with tense arousal.

Discussion

CPTpain acutely increased tense arousal and state anxiety, consistent with previous results implicating the reciprocal interaction of state anxiety and acute painful sensations and the role of pain in augmenting tense arousal. These results may indicate a psychological process which predisposes the hypervigilant to developing greater acute pain, resulting in positive feedback, greater pain and anxiety.

Dynamic processes of mindfulness-based alterations in pain perception

Mindfulness-based processes have been shown to enhance attention and related behavioral responses, including analgesia, which is discussed as an effective method in the context of pain interventions. In the present review, we introduce the construct of mindfulness, delineating the concepts, factors, and processes that are summarized under this term and might serve as relevant components of the underlying mechanistic pathways in the field of pain. We also discuss how differences in factors such as definitions of mindfulness, study design, and strategies in mindfulness-based attention direction may need to be considered when putting the findings from previous studies into a whole framework. In doing so, we capitalize on a potential dynamic process model of mindfulness-based analgesia. In this respect, the so-called mindfulness-based analgesia may initially result from improved cognitive regulation strategies, while at later stages of effects may be driven by a reduction of interference between both cognitive and affective factors. With increasing mindfulness practice, pathways and mechanisms of mindfulness analgesia may change dynamically, which could result from adaptive coping. This is underlined by the fact that the neural mechanism of mindfulness analgesia is manifested as increased activation in the ACC and aINS at the beginner level while increased activation in the pINS and reduced activation in the lPFC at the expert level.

Mind-body practices, interoception and pain: a scoping review of behavioral and neural correlates

OBJECTIVE

Chronic pain is a significant source of suffering in the United States, and many individuals increasingly turn towards yoga for pain relief. However, little is known regarding how yoga improves pain. Herein we seek to examine the scope of the literature linking mind-body practices, pain and interoception; an emerging mechanism by which yoga may improve chronic pain.

METHODS

This scoping review followed the five-stage methodological framework proposed by Arksey and O'Malley to examine behavioral and neural correlates of interoception in mind-body practices and pain. A broad search of the Pubmed, CINAHL, SportDiscus, Scopus, PsychInfo, and SocIndex databases was conducted, utilizing three clusters of search terms: (1) interoceptive terms, (2) mind-body terms, and (3) pain terms.

RESULTS

A combined total of 690 articles were screened, and 24 findings included for analysis. Sixteen studies examined interoceptive outcomes in response to mind-body practices for chronic pain, and 8 studies examined interoceptive outcomes in response to evoked-pain tasks in experienced mind-body practitioners. Only three studies linked yoga, interoception and pain.

CONCLUSION

This review relied on the broader mind-body literature to inform our analyses as the literature examining yoga, pain and interoception remains limited. Interoceptive techniques including attending to and acceptance of bodily sensations, appear to be key therapeutic mechanisms in mind-body practices for chronic pain. Future yoga-based interventions would benefit examining interoceptive outcomes and integrating interoceptive strategies to facilitate the pain-modulating benefits of yoga.

A randomized controlled trial of mindfulness-based stress reduction on academic resilience and performance in college students

OBJECTIVE

The transition into college can pose barriers for student success. We examined the impact of mindfulness-based stress reduction (MBSR) compared to an active and no treatment control group, respectively, on stressor appraisals, academic persistence, and performance in unversity students.

PARTICIPANTS

Students were randomly assigned to receive MBSR (n = 29), study skills active control (n = 27), or no treatment (n = 29).

METHOD

Participants reported stressor appraisals and academic persistence pre- and post-intervention. Semester grade point average (GPA) and enrollment was also obtained.

RESULTS

Academic stressor appraisals did not vary by group. MBSR was protective against depleted academic persistence, whereas academic persistence decreased in the control groups. Enrollment rates remained unchanged in the MBSR group, but increased in the active control relative to no treatment. Finally, GPA improved in the MBSR group, but not controls.

CONCLUSIONS

Findings suggest that MBSR confers some benefits for resilience in university students.

Effectiveness of Mindfulness-acceptance-commitment based approach for Rumination, Cognitive Flexibility and Sports Performance of Elite Players of Beach Soccer: A Randomized Controlled Trial with 2-months Follow-up

Background/Objective

There is little research on the effectiveness of new approaches to psychology, including mindfulness-acceptance-commitment, especially in team disciplines. Therefore, this study compared mindfulness-acceptance and commitment-based approaches to rumination, cognitive flexibility, and sports performance of elite beach soccer players during a two-month follow-up.

Methods

The research design consisted of a randomized controlled trial (RCT), with follow-up. Thus, 34 players of the premier league of beach soccer were randomly divided into intervention and control groups based on mindfulness acceptance and commitment. The experimental group exercises consisted of one session per week for 7 weeks and daily homework. Participants filled out the questionnaires of the Ruminative Response Scale, Cognitive Flexibility Inventory, and Sports Performance Questionnaire before, after, and at two months of follow-up of the intervention.

Results

Multivariate Analysis of Variance (MANOVA) and Analysis of Variance (ANOVA) with repeated measures were used to evaluate the changes over time and compare the scores of the subjects of the two groups. The results showed a significant difference in mindfulness-acceptance and commitment intervention in the experimental group on pre- vs. post-test and pre-test vs. follow-up scores of research variables. Also, a comparison of groups using independent T-test analysis showed a significant effect of mindfulness-acceptance and commitment exercises on research variables in the experimental group in the post-test and follow-up stages.

Conclusion

Findings suggest that mindfulness, commitment, and acceptance exercises can be used as a new method to reduce rumination and increase cognitive flexibility and sports performance of elite beach soccer players.

A neurophenomenological approach to non-ordinary states of consciousness: hypnosis, meditation, and psychedelics

No contemporary unifying framework has been provided for the study of non-ordinary states of consciousness (NSCs) despite increased interest in hypnosis, meditation, and psychedelics. NSCs induce shifts in experiential contents (what appears to the experiencer) and/or structure (how it appears). This can allow the investigation of the plastic and dynamic nature of experience from a multiscale perspective that includes mind, brain, body, and context. We propose a neurophenomenological (NP) approach to the study of NSCs which highlights their role as catalysts of transformation in clinical practice by refining our understanding of the relationships between experiential (subjective) and neural dynamics. We outline the ethical implications of the NP approach for standard conceptions of health and pathology as well as the crucial role of experience-based know-how in NSC-related research and application.

The Effectiveness of Mindful Hypnotherapy on Psychological Inflexibility, Pain Acceptance, Headache Disability and Intensity in Females with Chronic Migraine Headache: A Randomized Clinical Trial

This study was a randomized controlled design and examined the feasibility and effectiveness of mindful hypnotherapy on psychological inflexibility, pain acceptance, headache disability, and headache intensity in patients with chronic migraine headaches. The sample consisted of 38 females with chronic migraine who were randomly assigned to mindful hypnotherapy and medical treatment as usual groups. Psychological inflexibility pain scale (PIPS), chronic pain acceptance questionnaire-revised (CPAQ-R), headache disability inventory (HDI), diary scale for headache, and short-form McGill pain questionnaire 2 (SF-MPQ-2) were administered at baseline and post-treatment in both groups. The psychological inflexibility mean (SD) score was 81.00 (12.15) at baseline, which significantly decreased to 53.28 (17.06) after the intervention (p < 0.001). Additionally, the mean (SD) score of the pain acceptance was 46.44 (11.16), which significantly increased to 73.61 (15.65) in post-intervention (p < 0.001). Furthermore, the mean (SD) score of headache disability was 73.55 (19.48), which significantly decreased to 23.33 (19.88) in post-intervention (p < 0.001). Finally, headache intensity was 7.33 (0.98) and 5.78 (1.83), which significantly decreased to 2.77 (2.04), and 1.38 (1.48) after the intervention based on the Diary Scale for Headache and McGill Pain Questionnaire (SF-MPQ-2), respectively (p < 0.001). In conclusion, the results show that mindful hypnotherapy is a feasible and effective treatment for chronic migraine.

Yoga and pain: A mind-body complex system

Introduction

The human body's response to pain is indicative of a complex adaptive system. Therapeutic yoga potentially represents a similar complex adaptive system that could interact with the pain response system with unique benefits.

Objectives

To determine the viability of yoga as a therapy for pain and whether pain responses and/or yoga practice should be considered complex adaptive systems.

Methods

Examination through 3 different approaches, including a narrative overview of the evidence on pain responses, yoga, and complex system, followed by a network analysis of associated keywords, followed by a mapping of the functional components of complex systems, pain response, and yoga.

Results

The narrative overview provided extensive evidence of the unique efficacy of yoga as a pain therapy, as well as articulating the relevance of applying complex systems perspectives to pain and yoga interventions. The network analysis demonstrated patterns connecting pain and yoga, while complex systems topics were the most extensively connected to the studies as a whole.

Conclusion

All three approaches support considering yoga a complex adaptive system that exhibits unique benefits as a pain management system. These findings have implications for treating chronic, pervasive pain with behavioral medicine as a systemic intervention. Approaching yoga as complex system suggests the need for research of mind-body topics that focuses on long-term systemic changes rather than short-term isolated effects.

Potential mechanisms underlying the accelerated cognitive decline in people with chronic low back pain: A scoping review

A growing body of evidence has shown that people with chronic low back pain (CLBP) demonstrate significantly greater declines in multiple cognitive domains than people who do not have CLBP. Given the high prevalence of CLBP in the ever-growing aging population that may be more vulnerable to cognitive decline, it is important to understand the mechanisms underlying the accelerated cognitive decline observed in this population, so that proper preventive or treatment approaches can be developed and implemented. The current scoping review summarizes what is known regarding the potential mechanisms underlying suboptimal cognitive performance and cognitive decline in people with CLBP and discusses future research directions. Five potential mechanisms were identified based on the findings from 34 included studies: (1) altered activity in the cortex and neural networks; (2) grey matter atrophy; (3) microglial activation and neuroinflammation; (4) comorbidities associated with CLBP; and (5) gut microbiota dysbiosis. Future studies should deepen the understanding of mechanisms underlying this association so that proper prevention and treatment strategies can be developed.

Development and validation of the sickle cell stress scale-adult

Disease-specific stress can partly explain Sickle Cell Disease (SCD) healthcare utilization. We developed and validated two measures of adult SCD-specific stress for research and clinical care. A large cohort of adults with SCD completed both the 3-item Likert-scale adapted from a previous disease stress measure and a 10-item Likert-scale questionnaire drafted specifically to measure SCD stress. They concurrently completed a psychosocial and health-related quality of life scale battery, then subsequently daily pain diaries. Diaires measured: daily intensity, distress and interference of pain; self-defined vaso-occlusive crises (VOC), opioid use, and types of healthcare utilization for up to 24 weeks. Analyses tested Cronbach's alpha, correlation of the three-item and 10-item stress scales with the concurrent battery, with percentages of pain days, VOC days, opioid use days, and healthcare utilization days, and correlation of baseline stress and 6-month stress for the 10-item scale. Cronbach's alpha was high for both the 3-item (0.73) and 10-item (0.83) SCD stress scales, test-retest correlation of 0.55, expected correlation with the concurrent battery, and correlation with diary-measured healthcare utilization over 6 months. The correlations with the 3-item scale were stronger, but only statistically significant for depression-anxiety. The correlation between the two stress scales was 0.59. Both the 3-item and the 10-item stress scales exhibited good face, construct, concurrent, and predictive validity as well as moderate test-retest reliability. Further scale validation should determine population norms and response to interventions.

Mindfulness Meditation in the Treatment of Chronic Pain

Chronic pain is a leading cause of disability in the United States. Limited efficacy associated with pharmacologic management and surgical interventions in refractory patients has led to further exploration of cognitive and behavioral interventions as both an adjunctive and primary therapeutic modality. Mindfulness-based meditation has shown to be effective in reducing pain in randomized studies of chronic pain patients as well as models of experimentally induced pain in healthy participants. These studies have revealed specific neural mechanisms which may explain both short-term and sustained pain relief associated with mindfulness-based interventions.

Open monitoring meditation alters the EEG gamma coherence in experts meditators: The expert practice exhibit greater right intra-hemispheric functional coupling

AIM

This study investigated the differences in frontoparietal EEG gamma coherence between expert meditators (EM) and naïve meditators (NM).

MATERIAL AND METHODS

This is a cross-sectional study with a sample of twenty-one healthy adults divided under two groups (experts meditators vs. naive-meditators), with analyzing the intra-hemispheric coherence of frontoparietal gamma oscillations by electroencephalography during the study steps: EEG resting-state 1, during the open presence meditation practice, and EEG resting-state 2.

RESULTS

The findings demonstrated greater frontoparietal EEG coherence in gamma for experts meditators in the Fp1-P3, F4-P4, F8-P4 electrode pairs during rest 1 and rest 2 (p ≤ 0.0083). In addition, we evidenced differences in the frontoparietal EEG coherence for expert meditators in F4-P4, F8-P4 during the meditation (p ≤ 0.0083).

CONCLUSION

Our results can support evidence that the connectivity of the right frontoparietal network acts as a biomarker of the enhanced Open monitoring meditation training.

Pain catastrophizing, pain sensitivity and fear of pain are associated with early life environmental unpredictability: a path model approach

BACKGROUND

Socioeconomic disadvantages in the childhood environment might strongly influence beliefs and behavior characterizing the adult years. When children experience unpredictable and adverse situations, they develop an unpredictability schema with the core belief that situations are unpredictable.

METHODS

In two studies, we examined the association of childhood socioeconomic disadvantages with self-reported pain sensitivity, pain catastrophizing, and pain-related fear. Multidimensional survey measures were used to assess environmental conditions experienced in childhood. In addition, participants completed the Pain Catastrophizing Scale, Pain Sensitivity Questionnaire, Body Awareness Questionnaire, Unpredictability Schema Questionnaire, and Fear of Pain Questionnaire. In Study 1 (N = 252), in separate models, we examined pain sensitivity and pain catastrophizing of a community sample of pain-free young individuals in association with their childhood experiences. In Study 2 (N = 293), in a new sample, but with a wider age range, we examined the association of early life socioeconomic disadvantages with pain-related fear. In both studies, the predictions were tested with Structural Equation Modeling. Our models constituted a path from childhood socioeconomic status and household unpredictability to pain variables via the factors of family resources, unpredictability schemas, and body awareness.

RESULTS AND CONCLUSIONS

The findings converged on the conclusion that individuals experiencing disadvantageous early life conditions tended to have an elevated level of pain catastrophizing, higher perceived sensitivity to pain, and higher level of pain-related fear. These associations were mediated by an unpredictability schema and body awareness.

Altered Pain Processing Associated with Administration of Dopamine Agonist and Antagonist in Healthy Volunteers

Striatal dopamine dysfunction is associated with the altered top-down modulation of pain processing. The dopamine D2-like receptor family is a potential substrate for such effects due to its primary expression in the striatum, but evidence for this is currently lacking. Here, we investigated the effect of pharmacologically manipulating striatal dopamine D2 receptor activity on the anticipation and perception of acute pain stimuli in humans. Participants received visual cues that induced either certain or uncertain anticipation of two pain intensity levels delivered via a CO₂ laser. Rating of the pain intensity and unpleasantness was recorded. Brain activity was recorded with EEG and analysed via source localisation to investigate neural activity during the anticipation and receipt of pain. Participants completed the experiment under three conditions, control (Sodium Chloride), D2 receptor agonist (Cabergoline), and D2 receptor antagonist (Amisulpride), in a repeated-measures, triple-crossover, double-blind study. The antagonist reduced an individuals’ ability to distinguish between low and high pain following uncertain anticipation. The EEG source localisation showed that the agonist and antagonist reduced neural activations in specific brain regions associated with the sensory integration of salient stimuli during the anticipation and receipt of pain. During anticipation, the agonist reduced activity in the right mid-temporal region and the right angular gyrus, whilst the antagonist reduced activity within the right postcentral, right mid-temporal, and right inferior parietal regions. In comparison to control, the antagonist reduced activity within the insula during the receipt of pain, a key structure involved in the integration of the sensory and affective aspects of pain. Pain sensitivity and unpleasantness were not changed by D2R modulation. Our results support the notion that D2 receptor neurotransmission has a role in the top-down modulation of pain.

Are mindfulness treatments effective for pain in cancer patients? A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Mindfulness-based interventions (MBIs) have been recently applied in pain management and cancer care. However, inconsistencies exist concerning the effectiveness of MBIs on pain control among cancer patients. Therefore, this study aimed to examine the efficacy of MBIs on pain in cancer patients via a systematic review and meta-analysis of randomized controlled trials (RCTs).

METHODS

Databases (MEDLINE, PubMed, Embase, CINAHL, PsycINFO, Cochrane Central Register of Controlled Trials and ClinicalTrials.gov) were searched using key terms related to pain, cancer and mindfulness. The primary outcome was pain intensity. Standardized mean difference (SMD) of each outcome with 95% confidence interval (95% CI) was calculated. The quality of evidence was assessed by GRADE assessment.

RESULTS

Ten RCTs with 843 participants were included. Significant pooled effects of MBIs on pain intensity were found at both short-term (SMD = -0.19, 95% CI [-0.33 to -0.04]) and long-term (SMD = -0.20, 95% CI [-0.35 to -0.05]) follow-up, whereas no significance was observed for pain interference. In subgroup analyses, significant intervention effects were only seen in clinic-based MBIs compared to remote MBIs, and pooled effects of MBIs in attenuating pain were discovered relative to passive rather than active comparators. GRADE ratings showed moderate certainty of evidence in MBIs for pain intensity but low for pain interference.

CONCLUSIONS

The efficacy of MBIs in reducing pain intensity among cancer patients was revealed in this meta-analysis, albeit with a small effect size. Future research is warranted to optimize mindfulness treatment for pain control in cancer patients with high methodological quality and a large sample size.

SIGNIFICANCE

The effect of MBIs on pain in cancer patients was demonstrated in our analysis, albeit with small effect sizes. High-quality RCTs are needed to verify the efficacy of MBIs on cancer patients or survivors with pain complaints. Future trials should take into account the specific pain outcome measures (pain intensity or pain interference), the approach of intervention provision (clinic-based or remote MBI, group or individual practice), the duration and frequency of interventions and the comparators (passive or active control arms).

Dorsolateral prefrontal cortex sensing analgesia

Chronic pain often has an unknown cause, and many patients with chronic pain learn to accept that their pain is incurable and pharmacologic treatments are only temporarily effective. Complementary and integrative health approaches for pain are thus in high demand. One such approach is soft touch, e.g., adhesion of pyramidal thorn patches in a pain region. The effects of patch adhesion on pain relief have been confirmed in patients with various types of pain. A recent study using near-infrared spectroscopy revealed that the dorsolateral prefrontal cortex (DLPFC), especially the left side, is likely to be inactivated in patients experiencing pain relief during patch treatment. Mindfulness meditation is another well-known complementary and integrative approach for achieving pain relief. The relation between pain relief due to mindfulness meditation and changes in brain regions, including the DLPFC, has long been examined. In the present review article, we survey the literature describing the effects of the above-mentioned complementary and integrative treatments on pain relief, and outline the important brain regions, including the DLPFC, that are involved in analgesia. We hope that the present article will provide clues to researchers who hope to advance neurosensory treatments for pain relief without medication.

Alterations in brain structure and function in patients with osteonecrosis of the femoral head: a multimodal MRI study

Background

Pain, a major symptom of osteonecrosis of the femoral head (ONFH), is a complex sensory and emotional experience that presents therapeutic challenges. Pain can cause neuroplastic changes at the cortical level, leading to central sensitization and difficulties with curative treatments; however, whether changes in structural and functional plasticity occur in patients with ONFH remains unclear.

Methods

A total of 23 ONFH inpatients who did not undergo surgery (14 males, nine females; aged 55.61 ± 13.79 years) and 20 controls (12 males, eight females; aged 47.25 ± 19.35 years) were enrolled. Functional indices of the amplitude of low-frequency fluctuation (ALFF), regional homogeneity (ReHo), and a structural index of tract-based spatial statistics (TBSS) were calculated for each participant. The probability distribution of fiber direction was determined according to the ALFF results.

Results

ONFH patients demonstrated increased ALFF in the bilateral dorsolateral superior frontal gyrus, right medial superior frontal gyrus, right middle frontal gyrus, and right supplementary motor area. In contrast, ONFH patients showed decreased ReHo in the left superior parietal gyrus and right inferior temporal gyrus. There were no significant differences in TBSS or probabilistic tractography.

Conclusion

These results indicate cerebral pain processing in ONFH patients. It is advantageous to use functional magnetic resonance imaging to better understand pain pathogenesis and identify new therapeutic targets in ONFH patients.

Surface-based map plasticity of brain regions related to sensory motor and pain information processing after osteonecrosis of the femoral head

Pain is one of the manifestations of hip disorder and has been proven to lead to the remodeling of somatotopic map plasticity in the cortex. However, most studies are volume-based which may lead to inaccurate anatomical positioning of functional data. The methods that work on the cortical surface may be more sensitive than those using the full brain volume and thus be more suitable for map plasticity study. In this prospective cross-sectional study performed in Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, China, 20 patients with osteonecrosis of the femoral head (12 males and 8 females, aged 56.80 ± 13.60 years) and 20 healthy controls (9 males and 11 females, aged 54.56 ± 10.23 years) were included in this study. Data of resting-state functional magnetic resonance imaging were collected. The results revealed that compared with healthy controls, compared with the healthy controls, patients with osteonecrosis of the femoral head (ONFH) showed significantly increased surface-based regional homogeneity (ReHo) in areas distributed mainly in the left dorsolateral prefrontal cortex, frontal eye field, right frontal eye field, and the premotor cortex and decreased surface-based ReHo in the right primary motor cortex and primary sensory cortex. Regions showing significant differences in surface-based ReHo values between the healthy controls and patients with ONFH were defined as the regions of interests. Seed-based functional connectivity was performed to investigate interregional functional synchronization. When the areas with decreased surface-based ReHo in the frontal eye field and right premotor cortex were used as the regions of interest, compared with the healthy controls, the patients with ONFH displayed increased functional connectivity in the right middle frontal cortex and right inferior parietal cortex and decreased functional connectivity in the right precentral cortex and right middle occipital cortex. Compared with healthy controls, patients with ONFH showed significantly decreased cortical thickness in the para-insular area, posterior insular area, anterior superior temporal area, frontal eye field and supplementary motor cortex and reduced volume of subcortical gray matter nuclei in the right nucleus accumbens. These findings suggest that hip disorder patients showed cortical plasticity changes, mainly in sensorimotor- and pain-related regions. This study was approved by the Medical Ethics Committee of Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine (approval No. 2018-041) on August 1, 2018.

The anatomy of pain and suffering in the brain and its clinical implications

Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage. Chronic pain, with a prevalence of 20-30 % is the major cause of human suffering worldwide, because effective, specific and safe therapies have yet to be developed. It is unevenly distributed among sexes, with women experiencing more pain and suffering. Chronic pain can be anatomically and phenomenologically dissected into three separable but interacting pathways, a lateral 'painfulness' pathway, a medial 'suffering' pathway and a descending pain inhibitory pathway. One may have pain(fullness) without suffering and suffering without pain(fullness). Pain sensation leads to suffering via a cognitive, emotional and autonomic processing, and is expressed as anger, fear, frustration, anxiety and depression. The medial pathway overlaps with the salience and stress networks, explaining that behavioural relevance or meaning determines the suffering associated with painfulness. Genetic and epigenetic influences trigger chronic neuroinflammatory changes which are involved in transitioning from acute to chronic pain. Based on the concept of the Bayesian brain, pain (and suffering) can be regarded as the consequence of an imbalance between the two ascending and the descending pain inhibitory pathways under control of the reward system. The therapeutic clinical implications of this simple pain model are obvious. After categorizing the working mechanisms of each of the available treatments (pain killers, psychopharmacology, psychotherapy, neuromodulation, psychosurgery, spinal cord stimulation) to 1 or more of the 3 pathways, a rational combination can be proposed of activating the descending pain inhibitory pathway in combination with inhibition of the medial and lateral pathway, so as to rebalance the pain (and suffering) pathways.

The Role of Expectations and Endogenous Opioids in Mindfulness-Based Relief of Experimentally Induced Acute Pain

OBJECTIVE

Expectations contribute to cognitive pain modulation through opioidergically mediated descending inhibition. Mindfulness meditation reduces pain independent of endogenous opioids, engaging unique corticothalamocortical mechanisms. However, it remains unknown whether expectations for pain relief predict mindfulness-induced analgesia and if these expectations are modified by endogenous opioids.

METHODS

In this secondary analysis of previously published work, 78 pain-free participants (mean age, 27 ± 7 years; 50% women) were randomized to a four-session mindfulness meditation or book listening regimen. Expectations for intervention-induced pain relief were assessed before and after each intervention. Pain ratings were examined after meditation or rest (control group) during noxious heat (49°C) and intravenous administration of saline placebo or the opioid antagonist naloxone (0.15 mg/kg bolus + 0.1 mg kg-1 h-1 infusion.

RESULTS

Mindfulness significantly lowered pain during saline and naloxone infusion. Higher expected pain relief from mindfulness predicted lower pain intensity (r(40) = -0.41, p = .009). The relationship between meditation-related expectations and pain intensity reductions was exhibited during naloxone (r(20) = -0.76, p < .001) but not saline (r(20) = -0.22, p = .36). Expectations for book listening-based analgesia did not significantly predict pain changes during saline (r(20) = -0.37, p = .11) or naloxone (r(18) = 0.26, p = .30) in the control group.

CONCLUSIONS

These novel findings demonstrate a significant role for expectations in mindfulness-based pain relief. However, this role was minimal during saline and stronger during opioid blockade, despite similar pain reductions. This supports growing evidence that mindfulness engages multiple mechanisms to reduce pain, suggesting that mindfulness might be an effective pain-reducing technique even for individuals with low expectations for pain relief.

Neural Mechanisms of Hypnosis and Meditation-Induced Analgesia: A Narrative Review

Meditation and hypnosis have both been found to attenuate pain; however, little is known about similarities and differences in the cognitive modulation of pain. Hypnotic and meditative states (e.g., mindfulness) reduce pain by sharing and overlapping multiple neuro-cognitive mechanisms, but they differ in many respects. While there are overlapping brain networks involved, the nature of these effects seems different. Both phenomena involve frontal modulation of pain-related areas. The role of the dorsolateral prefrontal cortex appears to depend, in hypnosis, on the type of suggestion given and, in meditation, on the level of practice. Whereas the anterior cingulate cortex seems to be a key node in both hypnosis and meditation, the dorsolateral prefrontal cortex appears to engage in hypnosis as a function of suggestion and, in meditation, as a function of proficiency.

Acceptance-Based Emotion Regulation Reduces Subjective and Physiological Pain Responses

Acceptance-based regulation of pain, which focuses on the allowing of pain and pain related thoughts and emotions, was found to modulate pain. However, results so far are inconsistent regarding different pain modalities and indices. Moreover, studies so far often lack a suitable control condition, focus on behavioral pain measures rather than physiological correlates, and often use between-subject designs, which potentially impede the evaluation of the effectiveness of the strategies. Therefore, we investigated whether acceptance-based strategies can reduce subjective and physiological markers of acute pain in comparison to a control condition in a within-subject design. To this end, participants (N = 30) completed 24 trials comprising 10 s of heat pain stimulation. Each trial started with a cue instructing participants to welcome and experience pain (acceptance trials) or to react to the pain as it is without employing any regulation strategies (control trials). In addition to pain intensity and unpleasantness ratings, heart rate (HR) and skin conductance (SC) were recorded. Results showed significantly decreased pain intensity and unpleasantness ratings for acceptance compared to control trials. Additionally, HR was significantly lower during acceptance compared to control trials, whereas SC revealed no significant differences. These results demonstrate the effectiveness of acceptance-based strategies in reducing subjective and physiological pain responses relative to a control condition, even after short training. Therefore, the systematic investigation of acceptance in different pain modalities in healthy and chronic pain patients is warranted.

Let it be: mindful acceptance down-regulates pain and negative emotion

Mindfulness training ameliorates clinical and self-report measures of depression and chronic pain, but its use as an emotion regulation strategy—in individuals who do not meditate—remains understudied. As such, whether it (i) down-regulates early affective brain processes or (ii) depends on cognitive control systems remains unclear. We exposed meditation-naïve participants to two kinds of stimuli: negative vs. neutral images and painful vs. warm temperatures. On alternating blocks, we asked participants to either react naturally or exercise mindful acceptance. Emotion regulation using mindful acceptance was associated with reductions in reported pain and negative affect, reduced amygdala responses to negative images and reduced heat-evoked responses in medial and lateral pain systems. Critically, mindful acceptance significantly reduced activity in a distributed, a priori neurologic signature that is sensitive and specific to experimentally induced pain. In addition, these changes occurred in the absence of detectable increases in prefrontal control systems. The findings support the idea that momentary mindful acceptance regulates emotional intensity by changing initial appraisals of the affective significance of stimuli, which has consequences for clinical treatment of pain and emotion.

Mindfulness meditation is related to sensory-affective uncoupling of pain in trained novice and expert practitioners

BACKGROUND

Mindfulness meditation can alleviate acute and chronic pain. It has been proposed that mindfulness meditation reduces pain by uncoupling sensory and affective pain dimensions. However, studies to date have reported mixed results, possibly due to a diversity of styles of and expertise in mindfulness meditation. Furthermore, the interrelations between mindfulness meditation and pain catastrophizing during acute pain remain little known.

METHODS

This cross-sectional study investigated the effect of a style of mindfulness meditation called Open Monitoring (OM) on sensory and affective pain experience by comparing novice (2-day formal training; average ~20 hr practice) to expert practitioners (>10.000 hr practice). We implemented a paradigm that was designed to amplify the cognitive-affective aspects of pain experience by the manipulation of pain anticipation and uncertainty of stimulus length (8 or 16 s thermal pain stimuli). We collected pain intensity and unpleasantness ratings and assessed trait pain catastrophizing with the Pain Catastrophizing Scale (PCS).

RESULTS

Across groups, mindfulness meditation reduced unpleasantness, but not intensity ratings compared to attentional distraction. Experts reported a lower score on PCS, reduced amplification of unpleasantness by long painful stimuli, and larger sensory-affective uncoupling than novices particularly during long painful stimuli. In experts, meditation-induced uncoupling spilled over the control condition. Across groups and task conditions, a higher score on PCS predicted lower sensory-affective uncoupling during long painful stimuli and higher ratings of pain intensity during short painful stimuli.

CONCLUSION

These findings suggest that mindfulness meditation specifically down-regulates pain affect as opposed to pain intensity, and that pain catastrophizing undermines sensory-affective uncoupling of pain.

SIGNIFICANCE

In this study, we found that a style of mindfulness meditation referred to as OM reduced unpleasantness but not intensity ratings compared to attentional distraction in trained novice (state effect) and expert meditators (state and trait effects). We also observed that trait pain catastrophizing scores predicted this sensory-affective uncoupling. These findings advance our understanding of the cognitive mechanisms underlying mindfulness meditation and can inform treatment strategies for chronic pain.

A Simple Pattern of Movement is not Able to Inhibit Experimental Pain in FM Patients and Controls: an sLORETA Study

Motor cortex activation seems to induce an analgesic effect on pain that would be different between patients with fibromyalgia (FM) and control subjects. This study was conducted to analyze the changes of the laser-evoked potentials (LEPs) induced during a finger tapping task in the FM patients and the controls employing a multi-dipolar analysis according to Standardized low resolution brain electromagnetic tomography (sLORETA) method. The LEPs from 38 FM patients and 21 controls were analyzed. The LEPs were recorded while subjects performed a slow and a fast finger tapping task. We confirmed that the difference between N1, N2 and P2 wave amplitudes between conditions and groups was not significant. In control subjects, the fast finger tapping task induced a modification of cortical source activation in the main areas processing laser stimulation from the moving hand independently from the movement speed. In summary, a simple and repetitive movement is not able to induce consistent inhibition of experimental pain evoked by the moving and the not moving hand in each group. It could interfere with LEP sources within the limbic area at least in control subjects, without inhibit cortical responses or explain the different pattern of motor and pain interaction in FM patients.

Reduced Fear-Conditioned Pain Modulation in Experienced Meditators: A Preliminary Study

OBJECTIVE

Mindfulness-based practice is a form of cognitive/affective training that may help reduce suffering by attenuating maladaptive anticipatory processes. This study's objective was to examine the pain modulating impact of classical fear learning in meditation practitioners.

METHODS

The hyperalgesic effects of pain expectation and uncertainty were assessed outside formal meditation in 11 experienced meditators (>1000 hours) compared with meditation-naive controls during a Pavlovian classical fear-conditioning paradigm involving two visual stimuli (CS+/CS-), one of which (CS+) co-terminated with a noxious electrical stimulus (unconditioned stimulus) on 50% of trials. A Rescorla-Wagner/Pearce-Hall hybrid model was fitted onto the conditioned skin conductance responses using computational modeling to estimate two learning parameters: expected shock probability and associability (i.e., uncertainty).

RESULTS

Using a scale ranging between 0 (no pain) and 100 (extremely painful), meditators reported less pain (M = 19.9, SE = 5.1 for meditators, M = 32.4, SE = 2.4 for controls) but had comparable spinal motor responses (nociceptive flexion reflex) to the unconditioned stimulus. Multilevel mediation analyses revealed that meditators also exhibited reduced hyperalgesic effects of fear learning on higher-order pain responses but comparable effects on the nociceptive flexion reflex. These results suggest that mindfulness affects higher-order perceptual processes to a greater extent than from descending inhibitory controls. Furthermore, meditators showed reduced hyperalgesic effects of fear conditioning with no significant group difference in conditioned learning as evidenced by discriminative anticipatory skin conductance responses and learning parameters derived from computational modeling.

CONCLUSIONS

These results highlight potential mechanisms underlying mindfulness-related hypoalgesia, relevant to clinical conditions in which repeated pain exposure might reinforce hyperalgesic processes through fear conditioning.

Brain mechanisms impacted by psychological therapies for pain: identifying targets for optimization of treatment effects

Psychological therapies, such as cognitive behavioral therapy, are widely used multifaceted approaches that have been shown to improve pain-related functioning. A small but growing number of studies have used brain imaging to support the use of psychological therapies for pain. Although these studies have led to an increased understanding of how therapies may engage neural systems, there are multiple technical and conceptual challenges to consider. Based on the current literature, several components of effective psychological therapies for pain may be supported by changes in neural circuitry, which are most consistently represented by diminished activation and/or reduced hyperconnectivity in brain regions related to pain processing, emotion, and cognitive control. Findings may vary based on methodological approaches used and may also differ depending on targets of treatment. To provide a nuanced understanding of the current literature, specific targets and components of effective treatments for which a neural basis has been investigated are reviewed. These treatment components include catastrophic thinking about pain, increasing self-efficacy, mindfulness, anxiety symptom reduction, and exposure-based approaches. In general, such strategies have the potential to normalize regional hyperactivations and reduce hyperconnectivity in brain regions associated with nociceptive processing, cognition, and emotion, although additional research is needed. By determining if there are indeed distinct brain mechanisms engaged by different components of psychological therapy and evidence for specific changes in neural function after these interventions, future therapies may be more optimally tailored for individuals afflicted with chronic pain.

The neural mechanisms of mindfulness-based pain relief: a functional magnetic resonance imaging-based review and primer

The advent of neuroimaging methodologies, such as functional magnetic resonance imaging (fMRI), has significantly advanced our understanding of the neurophysiological processes supporting a wide spectrum of mind–body approaches to treat pain. A promising self-regulatory practice, mindfulness meditation, reliably alleviates experimentally induced and clinical pain. Yet, the neural mechanisms supporting mindfulness-based pain relief remain poorly characterized. The present review delineates evidence from a spectrum of fMRI studies showing that the neural mechanisms supporting mindfulness-induced pain attenuation differ across varying levels of meditative experience. After brief mindfulness-based mental training (ie, less than 10 hours of practice), mindfulness-based pain relief is associated with higher order (orbitofrontal cortex and rostral anterior cingulate cortex) regulation of low-level nociceptive neural targets (thalamus and primary somatosensory cortex), suggesting an engagement of unique, reappraisal mechanisms. By contrast, mindfulness-based pain relief after extensive training (greater than 1000 hours of practice) is associated with deactivation of prefrontal and greater activation of somatosensory cortical regions, demonstrating an ability to reduce appraisals of arising sensory events. We also describe recent findings showing that higher levels of dispositional mindfulness, in meditation-naïve individuals, are associated with lower pain and greater deactivation of the posterior cingulate cortex, a neural mechanism implicated in self-referential processes. A brief fMRI primer is presented describing appropriate steps and considerations to conduct studies combining mindfulness, pain, and fMRI. We postulate that the identification of the active analgesic neural substrates involved in mindfulness can be used to inform the development and optimization of behavioral therapies to specifically target pain, an important consideration for the ongoing opioid and chronic pain epidemic.

The Role of Heart Rate Variability in Mindfulness-Based Pain Relief

Mindfulness meditation is a self-regulatory practice premised on sustaining nonreactive awareness of arising sensory events that reliably reduces pain. Yet, the specific analgesic mechanisms supporting mindfulness have not been comprehensively disentangled from the potential nonspecific factors supporting this technique. Increased parasympathetic nervous system (PNS) activity is associated with pain relief corresponding to a number of cognitive manipulations. However, the relationship between the PNS and mindfulness-based pain attenuation remains unknown. The primary objective of the present study was to determine the role of high-frequency heart rate variability (HF HRV), a marker of PNS activity, during mindfulness-based pain relief as compared to a validated, sham-mindfulness meditation technique that served as a breathing-based control. Sixty-two healthy volunteers (31 females; 31 males) were randomized to a 4-session (25 min/session) mindfulness or sham-mindfulness training regimen. Before and after each group's respective training, participants were administered noxious (49°C) and innocuous (35°C) heat to the right calf. HF HRV and respiration rate were recorded during thermal stimulation and pain intensity and unpleasantness ratings were collected after each stimulation series. The primary analysis revealed that during mindfulness meditation, higher HF HRV was more strongly associated with lower pain unpleasantness ratings when compared to sham-mindfulness meditation (B = -.82, P = .04). This finding is in line with the prediction that mindfulness-based meditation engages distinct mechanisms from sham-mindfulness meditation to reduce pain. However, the same prediction was not confirmed for pain intensity ratings (B = -.41). Secondary analyses determined that mindfulness and sham-mindfulness meditation similarly reduced pain ratings, decreased respiration rate, and increased HF HRV (between group ps < .05). More mechanistic work is needed to reliably determine the role of parasympathetic activation in mindfulness-based pain relief as compared to other meditative techniques. Perspective: Mindfulness has been shown to engage multiple mechanisms to reduce pain. The present study extends on this work to show that higher HRV is associated with mindfulness-induced reductions in pain unpleasantness, but not pain intensity ratings, when compared to sham-mindfulness meditation. These findings warrant further investigation into the mechanisms engaged by mindfulness as compared to placebo.

A preliminary validation of the Swedish version of the Pain Catastrophizing Scale for Children (PCS-C) for children and adolescents with cancer

Objectives: Pain is reported as one of the most common and difficult symptoms for children and adolescents with cancer to cope with. Pain catastrophizing has been identified as a process clearly related to pain intensity and disability. The Pain Catastrophizing Scale for Children (PCS-C) has been validated in several languages and populations but remains to be validated in pediatric oncology. The aim of the study was to validate a Swedish version of the PCS-C for children and adolescents with cancer.

Methods: All children, 7–18 years of age, being treated for cancer in Sweden at the time of the study were invited to participate. Study material was sent out to the registered address. Internal consistency, test–retest reliability and convergent validity were calculated. Factor structure was examined using principal component analysis (PCA). Descriptive statistics were used to investigate background data and norm values.

Results: 61 children/adolescents were included in the analyses. The results did not support the original three-factor structure of the PCS-C, but rather suggested that a two-factor structure excluding item 8 best represented the data. The internal consistency of that solution was good (α=0.87), the test–rest reliability was excellent (ICC=0.75) and convergent validity was demonstrated (r=0.46). The mean (SD) for the PCS-C in the sample was 19.1 (9.2), without item 8. A statistically significant difference was shown between genders, where girls reported a higher level of pain catastrophizing than boys. No difference was found with regard to age.

Discussion: The Swedish version of the PCS-C is now preliminarily validated for children and adolescents with cancer, for whom gender- and age-specific norm values are now available. Questions remain regarding the optimal factor structure of the PCS-C.

What are the known effects of yoga on the brain in relation to motor performances, body awareness and pain? A narrative review

OBJECTIVE

The current body of literature was reviewed to evaluate the effects of yoga on the brain in relation to motor performance, body awareness and pain.

BACKGROUND

Yoga has been increasingly popular in the Western countries especially for its unique integration of the mind and body. Yoga has been studied more intensely in the last decade. Although it has been shown to improve cognitive functions, few studies have looked into the effects of yoga on improving motor performance, body awareness or pain and the possible underlying brain mechanisms associated with them.

METHODS

A search of the current literature was made using keywords such as: "yoga brain motor", "yoga brain pain", "effects yoga brain" and "effects yoga brain motor performance". The findings were then discussed in relation to motor performance, body awareness and pain and their reported mechanisms of action on the brain.

RESULTS

A total of 61 articles were selected, out of which 29 were excluded because they did not meet our criteria. A total of thirty-two articles were included in this review, which we further subdivided by focus: motor performance (n = 10), body awareness (n = 14) and pain (n = 8).

DISCUSSION

Our review shows that yoga has a positive effect on learning rate, speed and accuracy of a motor task by increasing attention and decreasing stress through a better control of sensorimotor rhythms. Yoga also seems to improve sensory awareness and interoception, regulate autonomic input, increase parasympathetic activity and promote self-regulation. Yoga was also shown to reduce the threat signal, increase pain tolerance, decrease pain unpleasantness and decrease the anxiety and distress associated with pain. Those changes are associated with the recruitment of specific brain areas such as the insula, the amygdala and the hippocampus.

CONCLUSION

Based on the studies reviewed in this report, we found that the practice of yoga seems to facilitate motor learning, to increase body awareness and to decrease pain. These are associated with a wide variety of changes in terms of brain activity and structure. Further studies are necessary to reveal its precise mechanism of action on the brain and to validate its wider application in clinical settings.

Evolution from four mental states to the highest state of consciousness: A neurophysiological basis of meditation as defined in yoga texts

This chapter provides a theoretical introduction to states of consciousness and reviews neuroscientific investigations of meditation. The different states of consciousness consist of four mental states, i.e., cancalata (random thinking), ekagrata (non-meditative focusing), dharna (focused meditation), and dhyana (meditation) as defined in yoga texts. Meditation is a self-regulated mental process associated with deep relaxation and increased internalized attention. Scientific investigations on meditation reported changes in electrophysiological signals and neuroimaging measures. But most outcomes of meditation studies showed inconsistent results, this may be due to heterogeneity in meditation methods and techniques evolved in the last 200 years. Traditionally, the features of meditation include the capacity to sustain a heightened awareness of thoughts, behaviors, emotions, and perceptions. Generally, meditation involves non-reactive effortless monitoring of the content of experience from moment to moment. Focused meditation practice involves awareness on a single object and open monitoring meditation is a non-directive meditation involved attention in breathing, mantra, or sound. Therefore, results of few empirical studies of advanced meditators or beginners remain tentative. This is an attempt to compile the meditation-related changes in electrophysiological and neuroimaging processes among experienced and novice practitioners.

A Systematic Review: Mindfulness Intervention for Cancer-Related Pain

Moderate-to-severe pain is a common problem experienced by patients with cancer. Although analgesic drugs are effective, adverse side effects are common and some analgesic drugs are addictive. Nonpharmacological treatment may be a way to treat cancer pain without causing negative side effects. Mindfulness is used as an effective nonpharmacological treatment to improve quality of life (QoL) and to address psychological problems including distress, anxiety, stress, and depression. However, the effect of mindfulness on pain severity has not been sufficiently investigated. Therefore, a systematic review was undertaken to describe the effectiveness of mindfulness interventions for pain and its underlying pathophysiologic mechanisms. The search was conducted in PubMed, Ovid MEDLINE, and CINAHL and included only empirical studies published from 2008 to 2017. Search terms included mindfulness, mindfulness-based intervention, meditation, cancer, pain, and cancer-related pain. Six studies met the search criteria. These studies tested several types of intervention including mindfulness-based stress reduction, mindfulness-based cognitive therapy, meditation with massage, and mindful awareness practices. Study outcomes include improved pain severity, anxiety, stress, depression, and QoL. However, most studies reviewed were conducted in the United States and Denmark. Further research is needed to test culturally appropriate mindfulness interventions to reduce pain.

Brain systems at the intersection of chronic pain and self-regulation

Chronic pain is a multidimensional experience with cognitive, affective, and somatosensory components that can be modified by expectations and learning. Individual differences in cognitive and affective processing, as well as contextual aspects of the pain experience, render chronic pain an inherently personal experience. Such individual differences are supported by the heterogeneity of brain representations within and across chronic pain pathologies. In this review, we discuss the complexity of brain representations of pain, and, with respect to this complexity, identify common elements of network-level disruptions in chronic pain. Specifically, we identify prefrontal-limbic circuitry and the default mode network as key elements of functional disruption. We then discuss how these disrupted circuits can be targeted through self-regulation and related cognitive strategies to alleviate chronic pain. We conclude with a proposal for how to develop personalized multivariate models of pain representation in the brain and target them with real-time neurofeedback, so that patients can explore and practice self-regulatory techniques with maximal efficiency.

Uncertain is worse: modulation of anxiety on pain anticipation by intensity uncertainty: evidence from the ERP study

To investigate the effect of uncertain information in the anticipation phase, this study used four cues to inform participants that they would face four kinds of subsequent electrical shocks: low-intensity shock, high-intensity shock, 50-50% chance of low-intensity or high-intensity shock, and no shock. Subjective evaluation on the anxiety elicited by different cues showed that uncertain cues aroused higher anxiety than certain cues, but the effect was observed only at low-intensity shock. The electroencephalogram data revealed that uncertain-shock cue elicited significantly larger stimulus-preceding negativity than certain-high-shock cue at the frontal site. The uncertain-shock cue and certain-high-shock cue both elicited significantly larger stimulus-preceding negativity than the cues of certain-low-shock and nonshock, respectively. Uncertain cues elicited significantly larger pain-evoked P2 than certain cues. The results implied that uncertainty of information regarding shock intensity captured more motivational engagement, aroused higher anxiety on anticipating for the electrical shock, and elicited higher perceived pain of shock stimulation.

Mindfulness Meditation for Fibromyalgia: Mechanistic and Clinical Considerations

PURPOSE OF REVIEW

Fibromyalgia is a disorder characterized by widespread pain and a spectrum of psychological comorbidities, rendering treatment difficult and often a financial burden. Fibromyalgia is a complicated chronic pain condition that requires a multimodal therapeutic approach to optimize treatment efficacy. Thus, it has been postulated that mind-body techniques may prove fruitful in treating fibromyalgia. Mindfulness meditation, a behavioral technique premised on non-reactive sensory awareness, attenuates pain and improves mental health outcomes. However, the impact of mindfulness meditation on fibromyalgia-related outcomes has not been comprehensively characterized. The present review delineates the existing evidence supporting the effectiveness and hypothesized mechanisms of mindfulness meditation in treating fibromyalgia-related outcomes.

RECENT FINDINGS

Mindfulness-based interventions premised on cultivating acceptance, non-attachment, and social engagement may be most effective in decreasing fibromyalgia-related pain and psychological symptoms. Mindfulness-based therapies may alleviate fibromyalgia-related outcomes through multiple neural, psychological, and physiological processes. Mindfulness meditation may provide an effective complementary treatment approach for fibromyalgia patients, especially when combined with other reliable techniques (exercise; cognitive behavioral therapy). However, characterizing the specific analgesic mechanisms supporting mindfulness meditation is a critical step to fostering the clinical validity of this technique. Identification of the specific analgesic mechanisms supporting mindfulness-based pain relief could be utilized to better design behavioral interventions to specifically target fibromyalgia-related outcomes.

Role of the Prefrontal Cortex in Pain Processing

The prefrontal cortex (PFC) is not only important in executive functions, but also pain processing. The latter is dependent on its connections to other areas of the cerebral neocortex, hippocampus, periaqueductal gray (PAG), thalamus, amygdala, and basal nuclei. Changes in neurotransmitters, gene expression, glial cells, and neuroinflammation occur in the PFC during acute and chronic pain, that result in alterations to its structure, activity, and connectivity. The medial PFC (mPFC) could serve dual, opposing roles in pain: (1) it mediates antinociceptive effects, due to its connections with other cortical areas, and as the main source of cortical afferents to the PAG for modulation of pain. This is a ‘loop’ where, on one side, a sensory stimulus is transformed into a perceptual signal through high brain processing activity, and perceptual activity is then utilized to control the flow of afferent sensory stimuli at their entrance (dorsal horn) to the CNS. (2) It could induce pain chronification via its corticostriatal projection, possibly depending on the level of dopamine receptor activation (or lack of) in the ventral tegmental area-nucleus accumbens reward pathway. The PFC is involved in biopsychosocial pain management. This includes repetitive transcranial magnetic stimulation, transcranial direct current stimulation, antidepressants, acupuncture, cognitive behavioral therapy, mindfulness, music, exercise, partner support, empathy, meditation, and prayer. Studies demonstrate the role of the PFC during placebo analgesia, and in establishing links between pain and depression, anxiety, and loss of cognition. In particular, losses in PFC grey matter are often reversible after successful treatment of chronic pain.

An Integrative Neuroscience Framework for the Treatment of Chronic Pain: From Cellular Alterations to Behavior

Chronic pain can result from many pain syndromes including complex regional pain syndrome (CRPS), phantom limb pain and chronic low back pain, among others. On a molecular level, chronic pain syndromes arise from hypersensitization within the dorsal horn of the spinal cord, a process known as central sensitization. Central sensitization involves an upregulation of ionotropic and metabotropic glutamate receptors (mGluRs) similar to that of long-term potentiation (LTP). Regions of the brain in which LTP occurs, such as the amygdala and hippocampus, are implicated in fear- and memory-related brain circuity. Chronic pain dramatically influences patient quality of life. Individuals with chronic pain may develop pain-related anxiety and pain-related fear. The syndrome also alters functional connectivity in the default-mode network (DMN) and salience network. On a cellular/molecular level, central sensitization may be reversed through degradative glutamate receptor pathways. This, however, rarely happens. Instead, cortical brain regions may serve in a top-down regulatory capacity for the maintenance or alleviation of pain. Specifically, the medial prefrontal cortex (mPFC), which plays a critical role in fear-related brain circuits, the DMN, and salience network may be the driving forces in this process. On a cellular level, the mPFC may form new neural circuits through LTP that may cause extinction of pre-existing pain pathways found within fear-related brain circuits, the DMN, and salience network. In order to promote new LTP connections between the mPFC and other key brain structures, such as the amygdala and insula, we propose a holistic rehabilitation program including cognitive behavioral therapy (CBT) and revolving around: (1) cognitive reappraisals; (2) mindfulness meditation; and (3) functional rehabilitation. Unlike current medical interventions focusing upon pain-relieving medications, we do not believe that chronic pain treatment should focus on reversing the effects of central sensitization. Instead, we propose here that it is critical to focus on non-invasive efforts to promote new neural circuits originating from the mPFC.

Enhancement of Meditation Analgesia by Opioid Antagonist in Experienced Meditators

OBJECTIVE

Studies have consistently shown that long-term meditation practice is associated with reduced pain, but the neural mechanisms by which long-term meditation practice reduces pain remain unclear. This study tested endogenous opioid involvement in meditation analgesia associated with long-term meditation practice.

METHODS

Electrical pain was induced with randomized, double-blind, cross-over administration of the opioid antagonist naloxone (0.15-mg/kg bolus dose, then 0.2-mg/kg per hour infusion dose) with 32 healthy, experienced meditation practitioners and a standardized open monitoring meditation.

RESULTS

Under saline, pain ratings were significantly lower during meditation (pain intensity: 6.41 ± 1.32; pain unpleasantness: 3.98 ± 2.17) than at baseline (pain intensity: 6.86 ±1.04, t(31) = 2.476, p = .019, Cohen's d = 0.46; pain unpleasantness: 4.96 ±1.75, t(31) = 3.746, p = .001, Cohen's d = 0.68), confirming the presence of meditation analgesia. Comparing saline and naloxone revealed significantly lower pain intensity (t(31) = 3.12, p = .004, d = 0.56), and pain unpleasantness (t(31) = 3.47, p = .002, d = 0.62), during meditation under naloxone (pain intensity: 5.53 ± 1.54; pain unpleasantness: 2.95 ± 1.88) than under saline (pain intensity: 6.41 ± 1.32; pain unpleasantness: 3.98 ± 2.17). Naloxone not only failed to eliminate meditation analgesia but also made meditation analgesia stronger.

CONCLUSIONS

Long-term meditation practice does not rely on endogenous opioids to reduce pain. Naloxone's blockade of opioid receptors enhanced meditation analgesia; pain ratings during meditation were significantly lower under naloxone than under saline. Possible biological mechanisms by which naloxone-induced opioid receptor blockade enhances meditation analgesia are discussed.