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To determine whether high school start time is associated with headache frequency in adolescents with migraine.
Learn More >Dorsal root ganglion stimulation (DRG-S) involves the electrical modulation of the somata of afferent neural fibers to treat chronic pain. DRG-S has demonstrated clinical efficacy at frequencies lower than typically used with spinal cord stimulation (SCS). In a clinical study, we found that the frequency of DRG-S can be tapered to a frequency as low as 4 Hz with no loss of efficacy. This review discusses possible mechanisms of action underlying effective pain relief with very low-frequency DRG-S.
Learn More >During self-induced pain, a copy of the motor information from the body's own movement may help predict the painful sensation and cause down-regulation of pain. This phenomenon, called sensory attenuation, enables the distinction between self-produced stimuli versus stimuli produced by others. Sensory attenuation has been shown to occur also during imagined self-produced movements, but this has not been investigated for painful sensations. In the current study, the pressure pain thresholds of 40 healthy participants aged 18-35 years were assessed when pain was induced by the experimenter (other), by themselves (self), or by the experimenter while imagining the pressure to be self-induced (imagery). The pressure pain was induced on the participants left lower thigh (quadriceps femoris) using a hand-held algometer. Significant differences were found between all conditions: other and self (P < 0.001), other and imagery (P < 0.001), and self and imagery (P = 0.004). The mean pressure pain threshold for other was 521.49 kPa (SE = 38.48), for self 729.57 kPa (SE = 32.32), and for imagery 618.88 kPa (SE = 26.67). Thus, sensory attenuation did occur both in the self and the imagery condition. The results of this study may have clinical relevance for understanding the mechanisms involved in the elevated pain thresholds seen in patients with self-injury behavior and the low pain thresholds seen in patients with chronic pain conditions. Imagery of sensory attenuation might also be used to alleviate the pain experience for patients undergoing procedural pain.
Learn More >Itch is an unpleasant and aversive somatosensory experience. These negative emotions significantly affect mental health in chronic itch patients. Therefore, it is important to understand the brain mechanism of negative emotions due to itch. The amygdala is an important hub of network to regulate negative emotions due to itch. However, the exact network remains unknown. Thus, using functional magnetic resonance imaging, we investigated what network the amygdala constitutes for processing itch in human brains. Twenty-five healthy subjects participated in the present study. Brain activity during electrical itch stimuli was measured by using functional magnetic resonance imaging. The amygdala exhibited increased functional connectivity during itch stimuli with key brain regions of the serotonergic system responsible for negative emotions (the medial habenula, median raphe nucleus) and the memory system to consolidate emotional experiences (the parahippocampus, perirhinal cortex). These systems may become therapeutic targets to prevent or reduce diminished mental health commonly seen in chronic itch patients.
Learn More >Trigeminal neuralgia (TN) is a chronic neuropathic pain that seriously affects the daily life of patients. There is increasing evidence that microRNAs (miRNAs) play an important role in the development of neuropathic pain.In this study, the TaqMan Low Density Array (TLDA) was used to analyze the serum miRNA levels of 28 TN patients, and 31 healthy people without any neuropathic pain were used as controls.The results showed that the expression profile of serum miRNA in TN patients was different from that in healthy controls. Compared with the control group, 13 miRNAs in the serum of TN patients were up-regulated and 115 miRNAs were down-regulated by >2 times. Quantitative reverse transcription PCR (RT-qPCR) analysis and receiver operating characteristic (ROC) curve were performed. The analysis further confirmed that the expression levels of 4 miRNAs, including miR-132-3p, miR-146b-5p, miR-155-5p, and miR-384, were significantly higher than those of healthy controls, and the difference was statistically significant.This study preliminarily confirmed the changes of serum miRNA expression profile in TN patients. Among them, 4 kinds of serum miRNA are likely to be related to the occurrence and development of TN.
Learn More >Anterolateral system neurons relay pain, itch, and temperature information from the spinal cord to pain-related brain regions, but the differentiation of these neurons and their specific contribution to pain perception remain poorly defined. Here, we show that most mouse spinal neurons that embryonically express the autonomic-system-associated Paired-like homeobox 2A (Phox2a) transcription factor innervate nociceptive brain targets, including the parabrachial nucleus and the thalamus. We define the Phox2a anterolateral system neuron birth order, migration, and differentiation and uncover an essential role for Phox2a in the development of relay of nociceptive signals from the spinal cord to the brain. Finally, we also demonstrate that the molecular identity of Phox2a neurons is conserved in the human fetal spinal cord, arguing that the developmental expression of Phox2a is a prominent feature of anterolateral system neurons.
Learn More >Prednisone is commonly used for initial short-term therapy of episodic cluster headaches before preventive medication such as verapamil becomes effective, but this strategy has not been tested in large randomised trials. We aimed to access the safety and efficacy of this treatment approach.
Learn More >Chronic musculoskeletal pain (CMP) causes significant health loss worldwide. Given that cultural factors may affect pain processing, it is key to have more information regarding CMP epidemiology in Latin America. In this study, we aimed to determine the prevalence of CMP and chronic widespread pain (CWP) in Chile.
Learn More >To compare spatial pain modulation capabilities between adolescents with and without migraine.
Learn More >To assess the safety and efficacy of AMG 301, an inhibitor of the pituitary adenylate cyclase-activating polypeptide (PACAP)-1 (PAC1) receptor, for prevention of migraine.
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