Neural plasticity
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Although referred pain or hypersensitivity has been repeatedly reported in irritable bowel syndrome (IBS) patients and experimental colitis rodents, little is known about the neural mechanisms. Spinal long-term potentiation (LTP) of nociceptive synaptic transmission plays a critical role in the development of somatic hyperalgesia in chronic pain conditions. Herein, we sought to determine whether spinal LTP contributes to the referral hyperalgesia in colitis rats and particularly whether electroacupuncture (EA) is effective to alleviate somatic hyperalgesia via suppressing spinal LTP. ⋯ Intriguingly, the threshold of C-fiber-evoked field potentials (CFEFP) was significantly reduced and the spinal LTP was exaggerated in the colitis group, both of which were restored by EA treatment. Taken together, visceral hypersensitivity and referral hindpaw hyperalgesia coexist in TNBS-induced colitis rats, which might be attributed to the enhanced LTP of nociceptive synaptic transmission in the spinal dorsal horn. EA at ST36 and ST37 could relieve visceral hypersensitivity and, in particular, attenuate referral hindpaw hyperalgesia by suppressing the enhanced spinal LTP.
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Chronic primary pain (CPP) is a group of diseases with long-term pain and functional disorders but without structural or specific tissue pathologies. CPP is becoming a serious health problem in clinical practice due to the unknown cause of intractable pain and high cost of health care yet has not been satisfactorily addressed. ⋯ The descending serotonergic neurons in the raphe nuclei target receptors along the descending pain circuits and exert either pro- or antinociceptive effects in different pain conditions. In this review, we summarize the possible underlying descending pain regulation mechanisms in CPP and the role of serotonin, thus providing evidence for potential application of analgesic medications based on the serotonergic system in CPP patients.
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Neuropathic pain after brachial plexus injury remains an increasingly prevalent and intractable disease due to inadequacy of satisfactory treatment strategies. A detailed mapping of cortical regions concerning the brain plasticity was the first step of therapeutic intervention. However, the specific mapping research of brachial plexus pain was limited. We aimed to provide some localization information about the brain plasticity changes after brachial plexus pain in this preliminary study. ⋯ We concluded that the entorhinal-hippocampus pathway, which was part of the Papez circuit, was involved in the functional integrated areas of brachial plexus pain processing. The regions in the "pain matrix" showed expected activation when applying instant nociceptive stimulus but remained silent in the resting status. This research confirmed the involvement of cognitive function, which brought novel information to the potential new therapy for brachial plexus pain.
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Patients with somatoform pain disorder (SPD) suffer from somatic pain that cannot be fully explained by specific somatic pathology. While the pain experience requires the integration of sensory and contextual processes, the cortical oscillations have been suggested to play a crucial role in pain processing and integration. The present study is aimed at identifying the abnormalities of spontaneous cortical oscillations among patients with SPD, thus for a better understanding of the ongoing brain states in these patients. ⋯ A significant correlation between parietal alpha oscillation and somatization severity was observed in SPD patients, after accounting for the influence of anxiety and depression. Functional connectivity analysis further revealed a greater frontoparietal connectivity of the resting-state alpha oscillations in SPD patients, which was indexed by the coherence between pairs of electrodes and the linear connectivity between pairs of eLORETA cortical sources. The enhanced resting-state alpha oscillation in SPD patients could be relevant with attenuated sensory information gating and excessive integration of pain-related information, while the enhanced frontoparietal connectivity could be reflecting their sustained attention to bodily sensations and hypervigilance to somatic sensations.
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Review Meta Analysis
Noninvasive Brain Stimulations for Unilateral Spatial Neglect after Stroke: A Systematic Review and Meta-Analysis of Randomized and Nonrandomized Controlled Trials.
Unilateral spatial neglect (USN) is the most frequent perceptual disorder after stroke. Noninvasive brain stimulation (NIBS) is a tool that has been used in the rehabilitation process to modify cortical excitability and improve perception and functional capacity. ⋯ The results suggest a benefit of NIBS on overall USN, and we conclude that rTMS is more efficacious compared to sham for USN after stroke.