Pain
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Studies in interictal migraine show either normal or impaired pain modulation, at the psychophysical level. To date, pain modulation in migraineurs has yet to be explored concurrent with imaging methods. We aimed to investigate brain activity associated with endogenous analgesia by functional magnetic resonance imaging in attack-free migraineurs. ⋯ Within groups, controls showed a significant CPM effect (Ts_alone: 6.15 ± 2.03 vs Ts_conditioned: 5.63 ± 1.97; P < 0.001), whereas migraineurs did not (Ts_alone: 5.60 ± 1.92 vs Ts_conditioned: 5.39 ± 2.30; P = 0.153); yet, both groups showed significant CPM-related decreased deactivation in prefrontal areas including the superior frontal gyrus and parietal regions including precuneus. The change in brain activity seems related to task demands rather than to pain reduction. The lack of group difference between migraineurs and controls in CPM and its related brain activity may result from (1) the specific CPM methodology used in this study, since migraineurs are reported to show various pain modulation efficiency for different test paradigms and/or (2) pathophysiological diversity of patients with migraine.
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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. ⋯ 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.
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Oxytocin (OT), known for its neurohormonal effects around birth, has recently been suggested for being a critical determinant in neurodevelopmental disorders. This hypothalamic neuropeptide exerts a potent analgesic effect through an action on the nociceptive system. This endogenous control of pain has an important adaptive value but might be altered by early life stress, possibly contributing to its long-term consequences on pain responses and associated comorbidities. ⋯ The involvement of epigenetic changes in these alterations was confirmed since neonatal treatment with the histone deacetylase inhibitor SAHA, not only normalized nociceptive sensitivities but also restored OT receptor-mediated stress-induced analgesia and the endogenous antihyperalgesia in inflamed NMS rats. There is growing evidence in the literature that early life stress might impair the nociceptive system ontogeny and function. This study suggests that these alterations might be restored while stimulating OT receptor signaling or histone deacetylase inhibitors, using molecules that are currently available or part of clinical trials for other pathologies.
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Research suggests that people living with HIV experience levels of pain disproportionate to the general population. Pain is a stressor that can negatively impact health-related quality of life. As the number of people aging with HIV increases, we must understand the dynamics of pain experiences among people living with HIV and how to effectively harness evidence-based treatments and supportive resources to enhance adaptive coping. ⋯ Results suggest that within-persons, experiences of daily social support reduce experiences of pain. Between-persons, attachment style may influence how individuals make use of social support in coping with experiences of pain. These findings imply a need to assess social well-being at the clinic level and also support tailored biopsychosocial approaches to pain management in HIV care settings.
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The left dorsolateral prefrontal cortex (DLPFC) is involved in the experience and modulation of pain, and may be an important node linking pain and cognition. Repetitive transcranial magnetic stimulation (rTMS) to the left DLPFC can reduce chronic and experimental pain. However, whether left DLPFC rTMS can influence the development of chronic pain is unknown. ⋯ There was a trend toward improved cognitive function with rTMS compared with sham (P = 0.057). These data indicate that repeated left DLPFC rTMS reduces the pain severity in a model of prolonged muscle pain. The findings may have implications for the development of sustained pain in clinical populations.