Pain
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Attentional disruption has been demonstrated using laboratory-induced pain, but has not been reliably established in everyday pain conditions. This study is the first to examine the effect of everyday acute headache on attention. Seventy-five frequent headache sufferers completed a flanker task, n-back task, attentional switching task, and dual task. ⋯ Headache did not, however, alter performance on the dual task, or the size of the attentional switching effect or result in a flanker effect. It must therefore be emphasised that headache pain appears to impair general task performance, irrespective of task complexity, rather than specific attentional mechanisms. Headache pain has an effect on the core cognitive components necessary for the successful completion of tasks, and in particular those involving the updating of the cognitive system.
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Fibromyalgia (FM), characterized by chronic widespread pain, is known to be associated with heightened responses to painful stimuli and atypical resting-state functional connectivity among pain-related regions of the brain. Previous studies of FM using resting-state functional magnetic resonance imaging (rs-fMRI) have focused on intrinsic functional connectivity, which maps the spatial distribution of temporal correlations among spontaneous low-frequency fluctuation in functional MRI (fMRI) resting-state data. In the current study, using rs-fMRI data in the frequency domain, we investigated the possible alteration of power spectral density (PSD) of low-frequency fluctuation in brain regions associated with central pain processing in patients with FM. rsfMRI data were obtained from 19 patients with FM and 20 age-matched healthy female control subjects. ⋯ According to the results, patients with FM exhibited significantly increased frequency power in the primary somatosensory cortex (S1), supplementary motor area (SMA), dorsolateral prefrontal cortex, and amygdala. In patients with FM, the increase in PSD did not show an association with depression or anxiety. Therefore, our findings of atypical increased frequency power during the resting state in pain-related brain regions may implicate the enhanced resting-state baseline neural activity in several brain regions associated with pain processing in FM.
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Randomized Controlled Trial
Reactive oxygen species contribute to neuropathic pain and locomotor dysfunction via activation of CamKII in remote segments following spinal cord contusion injury in rats.
In this study, we examined whether blocking spinal cord injury (SCI)-induced increases in reactive oxygen species (ROS) by a ROS scavenger would attenuate below-level central neuropathic pain and promote recovery of locomotion. Rats with T10 SCI developed mechanical allodynia in both hind paws and overproduction of ROS, as assayed by Dhet intensity, in neurons in the lumbar 4/5 dorsal horn ((∗)P<0.05). To scavenge ROS, phenyl-N-tert-butylnitrone (PBN, a ROS scavenger) was administered immediately after SCI and for 7 consecutive days (early treatment) by either intrathecal (it; 1 and 3mg) or systemic (ip; 10, 50 and 100mg) injections. ⋯ Both SCI and t-BOOH treatment groups showed significantly increased phospho-CamKII (pCamKII) expression in neurons and KN-93 (an inhibitor of pCamKII) significantly attenuated mechanical allodynia ((∗)P<0.05). In addition, high doses of PBN significantly promoted the recovery of locomotion ((∗)P<0.05). In conclusion, the present data suggest that overproduction of ROS contribute to sensory and motor abnormalities in remote segments below the lesion after thoracic SCI.
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Dysmenorrhea is the most prevalent gynecological disorder in women of child-bearing age. Dysmenorrhea is associated with central sensitization and functional and structural changes in the brain. Our recent brain morphometry study disclosed that dysmenorrhea is associated with trait-related abnormal gray matter (GM) changes, even in the absence of menstrual pain, indicating that the adolescent brain is vulnerable to menstrual pain. ⋯ Volume changes in regions involved in the regulation of endocrine function and pain transmission correlated with the menstrual pain experience scores. Our results demonstrated that short-lasting cyclic menstrual pain is associated not only with trait-related but also rapid state-related structural alterations in the brain. Considering the high prevalence rate of menstrual pain, these findings mandate a great demand to revisit dysmenorrhea with regard to its impact on the brain and other clinical pain conditions.