Disentangling self from pain: mindfulness meditation-induced pain relief is driven by thalamic-default mode network decoupling

Effects of meditation on neural responses to pain: A systematic review and meta-analysis of fMRI studies

This systematic review investigates the impact of meditation on neural responses to pain, as measured by functional magnetic resonance imaging (fMRI). Up to March 2024, we conducted searches across four databases for human studies implementing fMRI to assess the efficacy of meditation for pain relief. Eighteen studies met the inclusion criteria. Our systematic review indicates that activation of the insula, anterior cingulate cortex, and orbitofrontal cortex is positively associated with meditation for pain relief, while activity in regions like the amygdala and medial prefrontal cortex is negatively correlated with pain relief. Meta-analyses consistently reveal the involvement of various brain regions, including the insula, putamen, amygdala, anterior cingulate cortex, precentral gyrus, postcentral gyrus, inferior parietal lobule, superior temporal gyrus, inferior frontal gyrus, and caudate nucleus, in meditation-induced alleviation of pain. These findings suggest ccthat meditation acts on specific brain regions related to pain, mood, and cognition, providing insight into the potential mechanisms underlying the pain-alleviating effects of meditation on both pain sensations and emotional experiences.

Disrupted Resting-State Functional Connectivity and Effective Connectivity of the Nucleus Accumbens in Chronic Low Back Pain: A Cross-Sectional Study

Purpose

Chronic low back pain (cLBP) is a recurring and intractable disease that is often accompanied by emotional and cognitive disorders such as depression and anxiety. The nucleus accumbens (NAc) plays an important role in mediating emotional and cognitive processes and analgesia. This study investigated the resting-state functional connectivity (rsFC) and effective connectivity (EC) of NAc and its subregions in cLBP.

Methods

Thirty-four cLBP patients and 34 age- and sex-matched healthy controls (HC) underwent resting-state functional magnetic resonance imaging (rs-fMRI). Seed-based rsFC and Dynamic Causal Modelling (DCM) were used to examine the alteration of the rsFC and EC of the NAc.

Results

Our results showed that the cLBP group had increased rsFC of the bilateral NAc-left superior frontal cortex (SFC), orbital frontal cortex (OFC), left angular gyrus, the left NAc-bilateral middle temporal gyrus, as well as decreased rsFC of left NAc-left supramarginal gyrus, right precentral gyrus, left cerebellum, brainstem (medulla oblongata), and right insula pathways compared with the HC; the results of the subregions were largely consistent with the whole NAc. In addition, the rsFC of the left NAc-left SFC was negatively correlated with Hamilton's Depression Scale (HAMD) scores (r = -0.402, p = 0.018), and the rsFC of left NAc-OFC was positively correlated with present pain intensity scores (r = 0.406, p = 0.017) in the cLBP group. DCM showed that the cLBP group showed significantly increased EC from the left cerebellum to the right NAc (p = 0.012) as compared with HC.

Conclusion

Overall, our findings demonstrate aberrant rsFC and EC between NAc and regions that are associated with emotional regulation and cognitive processing in individuals with cLBP, underscoring the pivotal roles of emotion and cognition in cLBP.

Pathology of pain and its implications for therapeutic interventions

Pain is estimated to affect more than 20% of the global population, imposing incalculable health and economic burdens. Effective pain management is crucial for individuals suffering from pain. However, the current methods for pain assessment and treatment fall short of clinical needs. Benefiting from advances in neuroscience and biotechnology, the neuronal circuits and molecular mechanisms critically involved in pain modulation have been elucidated. These research achievements have incited progress in identifying new diagnostic and therapeutic targets. In this review, we first introduce fundamental knowledge about pain, setting the stage for the subsequent contents. The review next delves into the molecular mechanisms underlying pain disorders, including gene mutation, epigenetic modification, posttranslational modification, inflammasome, signaling pathways and microbiota. To better present a comprehensive view of pain research, two prominent issues, sexual dimorphism and pain comorbidities, are discussed in detail based on current findings. The status quo of pain evaluation and manipulation is summarized. A series of improved and innovative pain management strategies, such as gene therapy, monoclonal antibody, brain-computer interface and microbial intervention, are making strides towards clinical application. We highlight existing limitations and future directions for enhancing the quality of preclinical and clinical research. Efforts to decipher the complexities of pain pathology will be instrumental in translating scientific discoveries into clinical practice, thereby improving pain management from bench to bedside.

The role of endogenous opioids in mindfulness and sham mindfulness-meditation for the direct alleviation of evoked chronic low back pain: a randomized clinical trial

Chronic low back pain (cLBP) is the most prevalent chronic pain condition. There are no treatments that haven been found to directly assuage evoked cLBP. To this extent, mindfulness-meditation is a promising pain therapy. Yet, it is unclear if meditation can be utilized to directly attenuate evoked chronic pain through endogenous opioids. A double-blind, randomized, and placebo-controlled clinical trial with a drug crossover design examined if mindfulness-meditation, as compared to sham mindfulness-meditation, attenuated straight leg-raise test evoked chronic pain during intravenous (0.15 mg/kg bolus + 0.15 mg/kg/hour maintenance) naloxone (opioid antagonist) and placebo-saline infusion. Fifty-nine individuals with cLBP (mean age = 46 years; 30 females) completed all study procedures. After the pre-intervention pain testing session, patients were randomized to a four-session (20-min/session) mindfulness (n = 30) or sham mindfulness-meditation (n = 29) intervention. After the interventions, mindfulness and sham mindfulness-meditation were associated with significant reductions in back pain during saline and naloxone infusion when compared to rest (non-meditation) in response to the cLBP-evoking straight leg-raise test. These results indicate that meditation directly reduces evoked chronic pain through non-opioidergic processes. Importantly, after the interventions, the mindfulness group reported significantly lower straight leg-raise induced pain than the sham mindfulness-meditation group during rest (non-meditation) and meditation. Mindfulness and sham mindfulness-meditation training was also associated with significantly lower Brief Pain Inventory severity and interference scores. The pain-relieving effects of mindfulness meditation were more pronounced than a robust sham-mindfulness meditation intervention, suggesting that non-reactive appraisal processes may be uniquely associated with improvements in chronic low-back pain.Trial Registration: ClinicalTrials.gov identifier: NCT04034004.

Re-examining the Mysterious Role of the Cerebellum in Pain

Pain is considered a multidimensional experience that embodies not merely sensation, but also emotion and perception. As is appropriate for this complexity, pain is represented and processed by an extensive matrix of cortical and subcortical structures. Of these structures, the cerebellum is gaining increasing attention. Although association between the cerebellum and both acute and chronic pain have been extensively detailed in electrophysiological and neuroimaging studies, a deep understanding of what functions are mediated by these associations is lacking. Nevertheless, the available evidence implies that lobules IV-VI and Crus I are especially pertinent to pain processing, and anatomical studies reveal that these regions connect with higher-order structures of sensorimotor, emotional, and cognitive function. Therefore, we speculate that the cerebellum exerts a modulatory role in pain via its communication with sites of sensorimotor, executive, reward, and limbic function. On this basis, in this review, we propose numerous ways in which the cerebellum might contribute to both acute and chronic pain, drawing particular attention to emotional and cognitive elements of pain. In addition, we emphasise the importance of advancing our knowledge about the relationship between the cerebellum and pain by discussing novel therapeutic opportunities that capitalize on this association.

Functional and Structural Abnormalities in the Pain Network of Generalized Anxiety Disorder Patients with Pain Symptoms

Pain symptoms significantly impact the well-being and work capacity of individuals with generalized anxiety disorder (GAD), and hinder treatment and recovery. Despite existing literature focusing on the neural substrate of pain and anxiety separately, further exploration is needed to understand the possible neuroimaging mechanisms of the pain symptoms in GAD patients. We recruited 73 GAD patients and 75 matched healthy controls (HC) for clinical assessments, as well as resting-state functional and structural magnetic resonance imaging scans. We defined a pain-related network through a published meta-analysis, including the insula, thalamus, periaqueductal gray, prefrontal cortex, anterior cingulate cortex, amygdala, and hippocampus. Subsequently, we conducted the regional homogeneity (ReHo) and the gray matter volume (GMV) within the pain-related network. Correlation analysis was then employed to explore associations between abnormal regions and self-reported outcomes, assessed using the Patient Health Questionnaire-15 (PHQ-15) and pain scores. We observed significantly increased ReHo in the bilateral insula but decreased GMV in the bilateral thalamus of GAD compared to HC. Further correlation analysis revealed a positive correlation between ReHo of the left anterior insula and pain scores in GAD patients, while a respective negative correlation between GMV of the bilateral thalamus and PHQ-15 scores. In summary, GAD patients exhibit structural and functional abnormalities in pain-related networks. The enhanced ReHo in the left anterior insula is correlated with pain symptoms, which might be a crucial brain region of pain symptoms in GAD.

Pain intensity and self-perceived burden mediate the relationship between family functioning and pain catastrophizing in patients with neuropathic pain

This cross-sectional study aimed to investigate the relationship between family functioning, pain intensity, self-perceived burden, and pain catastrophizing. Moreover, we also wanted to explore the multiple mediating roles of pain intensity and self-perceived burden. From October 2022 to March 2023, 252 Chinese people with neuropathic pain completed face-to-face questionnaires to assess family functioning, pain intensity, self-perceived burden, and pain catastrophizing. Data analysis was done using descriptive statistics and a structural equation model. The results showed better family functioning was significantly associated with more intense pain, less self-perceived burden, and less pain catastrophizing. Mediation analysis showed that family functioning could indirectly affect pain catastrophizing through pain intensity and self-perceived burden in addition to a direct effect on pain catastrophizing. Moreover, the mediating variable of pain intensity played a masking role. These findings suggest that good family functioning can effectively reduce the self-perceived burden and pain catastrophizing in patients with neuropathic pain. However, family functioning cannot show its maximum effectiveness, and it may be necessary to construct a model of family functioning suitable for patients with neuropathic pain in the future.

Relationships between Self-Talk, Inner Speech, Mind Wandering, Mindfulness, Self-Concept Clarity, and Self-Regulation in University Students

In this study, the researchers explored novel relationships between the self-related processes of self-talk, inner speech, self-concept clarity, mindfulness, mind wandering, and self-regulation. Using self-report questionnaires (n = 227), we found a small positive association between inner speech use and mind wandering, as well as a medium positive association of mindfulness with self-regulation, in accordance with claims made in the literature. We found a medium positive relationship between mindfulness awareness and inner speech responses, potentially because mindfulness awareness represents an active state of self-focus, requiring verbal self-directed probes. Conversely, the correlations between reports of inner speech use and mindfulness acceptance were medium and negatively associated, perhaps because self-acceptance is a less active process that does not require as much self-directed speech as acquiring self-awareness, or perhaps self-acceptance consists of silencing the mind. Furthermore, the mindfulness-acceptance responses were negatively associated with mind wandering but positively correlated with self-concept clarity and self-regulation (all significant and of medium strength). Another noteworthy result was that mind wandering was negatively correlated with self-concept clarity and self-regulation, in accordance with the view that mind wandering represents a self-escape mechanism and thus impedes the transparency of one's self-view and efforts at controlling oneself. This study pieces together what has been presented in the literature, examining variables that are typically studied in isolation. Further, these results have implications for the future study of self-regulation in that self-focused attention, self-acceptance, and self-concept clarity may be mediators on the paths between self-talk or inner speech use and self-regulation.

WITHDRAWN: I feel your pain: Higher empathy is associated with higher posterior default mode network activity

The authors discovered an error in the primary analysis and have withdrawn the results from this version of the investigation.

Multimodal non-invasive non-pharmacological therapies for chronic pain: mechanisms and progress

BACKGROUND

Chronic pain conditions impose significant burdens worldwide. Pharmacological treatments like opioids have limitations. Non-invasive non-pharmacological therapies (NINPT) encompass diverse interventions including physical, psychological, complementary and alternative approaches, and other innovative techniques that provide analgesic options for chronic pain without medications.

MAIN BODY

This review elucidates the mechanisms of major NINPT modalities and synthesizes evidence for their clinical potential across chronic pain populations. NINPT leverages peripheral, spinal, and supraspinal mechanisms to restore normal pain processing and limit central sensitization. However, heterogeneity in treatment protocols and individual responses warrants optimization through precision medicine approaches.

CONCLUSION

Future adoption of NINPT requires addressing limitations in standardization and accessibility as well as synergistic combination with emerging therapies. Overall, this review highlights the promise of NINPT as a valuable complementary option ready for integration into contemporary pain medicine paradigms to improve patient care and outcomes.

Perspective on salutogenic approaches to persistent pain with a focus on mindfulness interventions

In this article, we provide a unique perspective on the use of mindfulness interventions in a whole health framework embedded within the theory of salutogenesis and the concept of painogenic environments. We argue that mindfulness is a valuable tool to bridge exploration of inner experiences of bodily pain with socio-ecological influences on thoughts and emotions. We outline research from neuroimaging studies that mindfulness techniques mediate neural processing and neuroplastic changes that alleviate pain and related symptoms. We also review evidence examining behavioural changes associated with mindfulness meditation providing evidence that it promotes self-regulatory activity, including the regulation and control of emotion and catalysation of health behaviour changes; both of which are important in chronic illness. Our viewpoint is that mindfulness could be a core element of salutogenic approaches to promote health and well-being for people living with pain because it rebuilds a fractured sense of cohesion. Mindfulness empowers people in pain to embrace their existence; shifting the focus away from pain and giving their lives meaning. We propose that integrating mindfulness into activities of daily living and individual or community-based activities will promote living well in the modern world, with or without pain; thus, promoting individual potential for fulfilment. Future research should consider the effects of mindfulness on people with pain in real-life settings, considering social, environmental, and economic factors using a broader set of outcomes, including self-efficacy, sense of coherence and quality of life.

Thalamocortical Mechanisms Underlying Real and Imagined Acupuncture

Both acupuncture and imagery have shown potential for chronic pain management. However, the mechanisms underlying their analgesic effects remain unclear. This study aims to explore the thalamocortical mechanisms underlying acupuncture and video-guided acupuncture imagery treatment (VGAIT), a combination of acupuncture and guided imagery, using the resting-state functional connectivity (rsFC) of three thalamic subdivisions-the ventral posterolateral thalamus (VPL), mediodorsal thalamus (MD), and motor thalamus subregion (Mthal)-associated with somatosensory, limbic, and motor circuity. Twenty-seven healthy individuals participated in a within-subject randomized crossover design study. Results showed that compared to sham acupuncture, real acupuncture altered the rsFC between the thalamus and default mode network (DMN) (i.e., mPFC, PCC, and precuneus), as well as the prefrontal and somatosensory cortex (SI/SII). Compared to the VGAIT control, VGAIT demonstrated greater rsFC between the thalamus and key nodes within the interoceptive network (i.e., anterior insula, ACC, PFC, and SI/SII), as well as the motor and sensory cortices (i.e., M1, SMA, and temporal/occipital cortices). Furthermore, compared to real acupuncture, VGAIT demonstrated increased rsFC between the thalamus (VPL/MD/Mthal) and task-positive network (TPN). Further correlations between differences in rsFC and changes in the heat or pressure pain threshold were also observed. These findings suggest that both acupuncture- and VGAIT-induced analgesia are associated with thalamocortical networks. Elucidating the underlying mechanism of VGAIT and acupuncture may facilitate their development, particularly VGAIT, which may be used as a potential remote-delivered pain management approach.

The Mindful Reappraisal of Pain Scale (MRPS): Validation of a New Measure of Psychological Mechanisms of Mindfulness-Based Analgesia

Objectives

Mindfulness is theorized to decrease the affective amplification of chronic pain by facilitating a shift from emotionally-laden, catastrophic pain appraisals of nociceptive input to reappraising chronic pain as an innocuous sensory signal that does not signify harm. Understanding of these hypothetical psychological mechanisms of mindfulness-based analgesia has been limited by a lack of direct measures. We conducted a series of psychometric and experimental studies to develop and validate the Mindful Reappraisal of Pain Sensations Scale (MPRS).

Methods

After item generation, we conducted exploratory and confirmatory factor analyses of the MRPS in samples of opioid-treated chronic pain patients both before (n=450; n=90) and after (n=222) participating in Mindfulness-Oriented Recovery Enhancement (MORE). We then examined the convergent and divergent validity of the MRPS. Finally, in data from a randomized clinical trial (n=250), the MRPS was tested as a mediator of the effects of MORE on reducing chronic pain severity.

Results

Exploratory and confirmatory factor analyses demonstrated the single-factor structure of the MRPS. The MRPS also evidenced convergent and divergent validity. Mindfulness training through MORE significantly increased MRPS scores relative to supportive psychotherapy (F4,425.03 = 16.15, p < .001). Changes in MRPS scores statistically mediated the effect of MORE on reducing chronic pain severity through 9-month follow-up.

Conclusions

Taken together, these studies demonstrate that the MRPS is a psychometrically sound and valid measure of novel analgesic mechanisms of mindfulness including attentional disengagement from affective pain appraisals and interoceptive exposure to pain sensations.