Does meditation reduce pain through a unique neural mechanism?

The Biology of Chronic Pain and Its Implications for Pain Neuroscience Education: State of the Art

Pain is an individualized experience for the person suffering from chronic pain. Significant strides have been made in the last few decades in understanding various biological changes that coincide with chronic pain. This state-of-the-art overview looks at the current evidence related to the biology of chronic pain and the implications these findings have on the delivery of pain neuroscience education (PNE). The paper summarizes the various (epi)genetic, neural, endocrine, and immune factors discovered and explored in the scientific literature concerning chronic pain. Each of these biological factors has various implications for the content and delivery of PNE. We discuss the future directions these biological factors have for the clinical implementation of PNE by linking the importance of behavior change, optimizing the learning environment, and using an individualized multimodal treatment approach with PNE. In addition, future directions for research of PNE based on these biological factors are provided with importance placed on individualized patient-centered care and how PNE can be used with traditional modes of care and growing trends with other care methods. PNE was originally and continues to be rooted in understanding chronic pain biology and how that understanding can improve patient care and outcomes.

Attention to breath sensations does not engage endogenous opioids to reduce pain

The endogenous opioidergic system is critically involved in the cognitive modulation of pain. Slow-breathing-based techniques are widely used nonpharmacological approaches to reduce pain. Yet, the active mechanisms of actions supporting these practices are poorly characterized. Growing evidence suggest that mindfulness-meditation, a slow-breathing technique practiced by nonreactively attending to breathing sensations, engages multiple unique neural mechanisms that bypass opioidergically mediated descending pathways to reduce pain. However, it is unknown whether endogenous opioids contribute to pain reductions produced by slow breathing. The present double-blind, placebo-controlled crossover study examined behavioral pain responses during mindfulness-meditation (n = 19), sham-mindfulness meditation (n = 20), and slow-paced breathing (n = 20) in response to noxious heat (49°C) and intravenous administration (0.15 mg/kg bolus + 0.1 mg/kg/hour maintenance infusion) of the opioid antagonist, naloxone, and placebo saline. Mindfulness significantly reduced pain unpleasantness ratings across both infusion sessions when compared to rest, but not pain intensity. Slow-paced breathing significantly reduced pain intensity and unpleasantness ratings during naloxone but not saline infusion. Pain reductions produced by mindfulness-meditation and slow-paced breathing were insensitive to naloxone when compared to saline administration. By contrast, sham-mindfulness meditation produced pain unpleasantness reductions during saline infusion but this effect was reversed by opioidergic antagonism. Sham-mindfulness did not lower pain intensity ratings. Self-reported "focusing on the breath" was identified as the operational feature particularly unique to the mindfulness-meditation and slow paced-breathing, but not sham-mindfulness meditation. Across all individuals, attending to the breath was associated with naloxone insensitive pain-relief. These findings provide evidence that slow breathing combined with attention to breath reduces pain independent of endogenous opioids.

Employing pain and mindfulness to understand consciousness: a symbiotic relationship

Consciousness, defined here as the quality of awareness of self and the corresponding sensory environment, is considered to be one of most enigmatic and contentious areas of scholarly dissection and investigation. The subjective experience of pain is constructed and modulated by a myriad of sensory, cognitive and affective dimensions. Thus, the study of pain can provide many inroads to a concept like consciousness that the traditional sense modalities do not. Mindfulness defined here as non-reactive awareness of the present moment, can uniquely control and/or modulate particular substrates of conscious experience. Thus, in combination with brain imaging methodologies, we propose that the interactions between pain and mindfulness could serve as a more comprehensive platform to disentangle the biological and psychological substrates of conscious experience. The present review provides a brief synopsis on how combining the study of pain and mindfulness can inform the study of consciousness, delineates the multiple, unique brain mechanisms supporting mindfulness-based pain relief, and describes how mindfulness uniquely improves the affective dimension of pain, an important consideration for the treatment of chronic pain.

Neural mechanisms supporting the relationship between dispositional mindfulness and pain

Interindividual differences in pain sensitivity vary as a function of interactions between sensory, cognitive-affective, and dispositional factors. Trait mindfulness, characterized as the innate capacity to nonreactively sustain attention to the present moment, is a psychological construct that is associated with lower clinical pain outcomes. Yet, the neural mechanisms supporting dispositional mindfulness are unknown. In an exploratory data analysis obtained during a study comparing mindfulness to placebo analgesia, we sought to determine whether dispositional mindfulness is associated with lower pain sensitivity. We also aimed to identify the brain mechanisms supporting the postulated inverse relationship between trait mindfulness and pain in response to noxious stimulation. We hypothesized that trait mindfulness would be associated with lower pain and greater deactivation of the default mode network. Seventy-six meditation-naive and healthy volunteers completed the Freiburg Mindfulness Inventory and were administered innocuous (35°C) and noxious stimulation (49°C) during perfusion-based functional magnetic resonance imaging. Higher Freiburg Mindfulness Inventory ratings were associated with lower pain intensity (P = 0.005) and pain unpleasantness ratings (P = 0.005). Whole brain analyses revealed that higher dispositional mindfulness was associated with greater deactivation of a brain region extending from the precuneus to posterior cingulate cortex during noxious heat. These novel findings demonstrate that mindful individuals feel less pain and evoke greater deactivation of brain regions supporting the engagement sensory, cognitive, and affective appraisals. We propose that mindfulness and the posterior cingulate cortex should be considered as important mechanistic targets for pain therapies.

Mindfulness meditation-based pain relief: a mechanistic account

Pain is a multidimensional experience that involves interacting sensory, cognitive, and affective factors, rendering the treatment of chronic pain challenging and financially burdensome. Further, the widespread use of opioids to treat chronic pain has led to an opioid epidemic characterized by exponential growth in opioid misuse and addiction. The staggering statistics related to opioid use highlight the importance of developing, testing, and validating fast-acting nonpharmacological approaches to treat pain. Mindfulness meditation is a technique that has been found to significantly reduce pain in experimental and clinical settings. The present review delineates findings from recent studies demonstrating that mindfulness meditation significantly attenuates pain through multiple, unique mechanisms-an important consideration for the millions of chronic pain patients seeking narcotic-free, self-facilitated pain therapy.

Mindfulness and headache: A "new" old treatment, with new findings

Background Mindfulness refers to a host of procedures that have been practiced for centuries, but only recently have begun to be applied to varied pain conditions, with the most recent being headache. Methods We reviewed research that incorporated components of mindfulness for treating pain, with a more in depth focus on headache disorders. We also examined literature that has closely studied potential physiological processes in the brain that might mediate the effects of mindfulness. We report as well preliminary findings of our ongoing trial comparing mindfulness alone to pharmacological treatment alone for treating chronic migraine accompanied by medication overuse. Results Although research remains in its infancy, the initial findings support the utility of varied mindfulness approaches for enhancing usual care for headache management. Our preliminary findings suggest mindfulness by itself may produce effects comparable to that of medication alone for patients with chronic migraine and medication overuse. Conclusions Much work remains to more fully document the role and long term value of mindfulness for specific headache types. Areas in need of further investigation are discussed.

Mindfulness Meditation-Based Pain Relief Employs Different Neural Mechanisms Than Placebo and Sham Mindfulness Meditation-Induced Analgesia

Mindfulness meditation reduces pain in experimental and clinical settings. However, it remains unknown whether mindfulness meditation engages pain-relieving mechanisms other than those associated with the placebo effect (e.g., conditioning, psychosocial context, beliefs). To determine whether the analgesic mechanisms of mindfulness meditation are different from placebo, we randomly assigned 75 healthy, human volunteers to 4 d of the following: (1) mindfulness meditation, (2) placebo conditioning, (3) sham mindfulness meditation, or (4) book-listening control intervention. We assessed intervention efficacy using psychophysical evaluation of experimental pain and functional neuroimaging. Importantly, all cognitive manipulations (i.e., mindfulness meditation, placebo conditioning, sham mindfulness meditation) significantly attenuated pain intensity and unpleasantness ratings when compared to rest and the control condition (p < 0.05). Mindfulness meditation reduced pain intensity (p = 0.032) and pain unpleasantness (p < 0.001) ratings more than placebo analgesia. Mindfulness meditation also reduced pain intensity (p = 0.030) and pain unpleasantness (p = 0.043) ratings more than sham mindfulness meditation. Mindfulness-meditation-related pain relief was associated with greater activation in brain regions associated with the cognitive modulation of pain, including the orbitofrontal, subgenual anterior cingulate, and anterior insular cortex. In contrast, placebo analgesia was associated with activation of the dorsolateral prefrontal cortex and deactivation of sensory processing regions (secondary somatosensory cortex). Sham mindfulness meditation-induced analgesia was not correlated with significant neural activity, but rather by greater reductions in respiration rate. This study is the first to demonstrate that mindfulness-related pain relief is mechanistically distinct from placebo analgesia. The elucidation of this distinction confirms the existence of multiple, cognitively driven, supraspinal mechanisms for pain modulation.

SIGNIFICANCE STATEMENT

Recent findings have demonstrated that mindfulness meditation significantly reduces pain. Given that the "gold standard" for evaluating the efficacy of behavioral interventions is based on appropriate placebo comparisons, it is imperative that we establish whether there is an effect supporting meditation-related pain relief above and beyond the effects of placebo. Here, we provide novel evidence demonstrating that mindfulness meditation produces greater pain relief and employs distinct neural mechanisms than placebo cream and sham mindfulness meditation. Specifically, mindfulness meditation-induced pain relief activated higher-order brain regions, including the orbitofrontal and cingulate cortices. In contrast, placebo analgesia was associated with decreased pain-related brain activation. These findings demonstrate that mindfulness meditation reduces pain through unique mechanisms and may foster greater acceptance of meditation as an adjunct pain therapy.

A Brief Mindfulness Meditation Training Increases Pain Threshold and Accelerates Modulation of Response to Tonic Pain in an Experimental Study

OBJECTIVE

Research shows that mindfulness meditation (MM) affects pain perception; however, studies have yet to measure patterns of change over time. We examined effects of MM on perception of experimental heat pain using multiple psychophysical indices, including pattern of change in response to tonic painful stimuli. We also tested the potential moderating role of baseline mindfulness.

METHOD

Forty participants were randomly assigned to a brief MM training or control group. We assessed: a) heat pain threshold (HPT), b) temperature which induces pain at a fixed, target intensity level, and c) response pattern over time to tonic heat pain.

RESULTS

Compared to control group, the MM group showed increased HPT and more rapid attenuation of pain intensity for tonic pain stimuli. Moderation analyses indicated that baseline mindfulness moderated effects of MM on HPT.

CONCLUSIONS

A brief MM intervention appears to affect perception of experimental pain both by increasing pain threshold and accelerating modulation of response. Findings may help elucidate mechanisms of MM for chronic pain.

The brain network reflecting bodily self-consciousness: a functional connectivity study

Several brain regions are important for processing self-location and first-person perspective, two important aspects of bodily self-consciousness. However, the interplay between these regions has not been clarified. In addition, while self-location and first-person perspective in healthy subjects are associated with bilateral activity in temporoparietal junction (TPJ), disturbed self-location and first-person perspective result from damage of only the right TPJ. Identifying the involved brain network and understanding the role of hemispheric specializations in encoding self-location and first-person perspective, will provide important information on system-level interactions neurally mediating bodily self-consciousness. Here, we used functional connectivity and showed that right and left TPJ are bilaterally connected to supplementary motor area, ventral premotor cortex, insula, intraparietal sulcus and occipitotemporal cortex. Furthermore, the functional connectivity between right TPJ and right insula had the highest selectivity for changes in self-location and first-person perspective. Finally, functional connectivity revealed hemispheric differences showing that self-location and first-person perspective modulated the connectivity between right TPJ, right posterior insula, and right supplementary motor area, and between left TPJ and right anterior insula. The present data extend previous evidence on healthy populations and clinical observations in neurological deficits, supporting a bilateral, but right-hemispheric dominant, network for bodily self-consciousness.

Mindfulness-based interventions for physical conditions: a narrative review evaluating levels of evidence

Research on mindfulness-based interventions (MBIs) for treating symptoms of a wide range of medical conditions has proliferated in recent decades. Mindfulness is the cultivation of nonjudgmental awareness in the present moment. It is both a practice and a way of being in the world. Mindfulness is purposefully cultivated in a range of structured interventions, the most popular of which is mindfulness-based stress reduction (MBSR), followed by mindfulness-based cognitive therapy (MBCT). This paper begins with a discussion of the phenomenological experience of coping with a chronic and potentially life-threatening illness, followed by a theoretical discussion of the application of mindfulness in these situations. The literature evaluating MBIs within medical conditions is then comprehensively reviewed, applying a levels of evidence rating framework within each major condition. The bulk of the research looked at diagnoses of cancer, pain conditions (chronic pain, low back pain, fibromyalgia, and rheumatoid arthritis), cardiovascular disease, diabetes, human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS), and irritable bowel syndrome. Most outcomes assessed are psychological in nature and show substantial benefit, although some physical and disease-related parameters have also been evaluated. The field would benefit from more adequately powered randomized controlled trials utilizing active comparison groups and assessing the moderating role of patient characteristics and program "dose" in determining outcomes.