Pain
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Research on family factors in paediatric pain has primarily focused on parents; the role of siblings has been largely ignored. This study examined whether sibling relationship quality was related to siblings' behaviours during experimental pain, and whether the behaviours of an observing sibling were related to children's pain outcomes. Ninety-two sibling dyads between 8 and 12 years old completed both observational and questionnaire measures of sibling relationship quality. ⋯ Greater levels of attending behaviours by the observing child was related to the sibling having a lower pain tolerance, and greater levels of coping/encouragement behaviours by the observing child was related to the sibling reporting greater pain intensity and fear during the CPT. Children with warmer/positive sibling relationships were more likely to respond to acute pain by shifting the focus away from their pain experience (eg, through distraction) when a sibling was present. Pain-focused behaviours by an observing sibling are related to greater child pain and fear during experimental pain.
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Expectations modulate the subjective experience of pain by increasing sensitivity to nociceptive inputs, an effect mediated by brain regions such as the insula. However, it is still unknown whether the neural structures underlying pain expectancy hold sensory-specific information or, alternatively, code for modality-independent features (eg, unpleasantness), potentially common with other negative experiences. We used functional magnetic resonance imaging to investigate neural activity underlying the expectation of different, but comparably unpleasant, pain and disgust. ⋯ At the brain level, this effect was mediated by the intermediate dysgranular section of the insula, whereas it was suppressed by more anterior agranular portions of the same region. Instead, no expectancy modulation was observed when the modality of the cue differed from that of the subsequent stimulus. Our data suggest that the insular cortex encodes prospective aversive events in terms of their modality-specific features, and whether they match with subsequent stimulations.
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Voltage-gated potassium (Kv) channels are increasingly recognised as key regulators of nociceptive excitability. Kcns1 is one of the first potassium channels to be associated with neuronal hyperexcitability and mechanical sensitivity in the rat, as well as pain intensity and risk of developing chronic pain in humans. Here, we show that in mice, Kcns1 is predominantly expressed in the cell body and axons of myelinated sensory neurons positive for neurofilament-200, including Aδ-fiber nociceptors and low-threshold Aβ mechanoreceptors. ⋯ After neuropathic injury, Kcns1 KO mice exhibited exaggerated mechanical pain responses and hypersensitivity to both noxious and innocuous cold, consistent with increased A-fiber activity. Interestingly, Kcns1 deletion also improved locomotor performance in the rotarod test, indicative of augmented proprioceptive signalling. Our results suggest that restoring Kcns1 function in the periphery may be of some use in ameliorating mechanical and cold pain in chronic states.
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Existing evidence of an association between effort-reward imbalance (ERI) at work and musculoskeletal pain is limited, preventing reliable conclusions about the magnitude and direction of the relation. In a large longitudinal study, we examined whether the onset of ERI is associated with subsequent onset of musculoskeletal pain among those free of pain at baseline, and vice versa, whether onset of pain leads to onset of ERI. Data were from the Swedish Longitudinal Occupational Survey of Health (SLOSH) study. ⋯ In the adjusted models, onset of ERI was associated with onset of neck-shoulder pain (relative risk [RR] 1.51, 95% confidence interval [CI] 1.21-1.89) and low back pain (RR 1.21, 95% CI 0.97-1.50). The opposite was also observed, as onset of neck-shoulder pain increased the risk of subsequent onset of ERI (RR 1.36, 95% CI 1.05-1.74). Our findings suggest that when accounting for the temporal order, the associations between ERI and musculoskeletal pain that affects life are bidirectional, implying that interventions to both ERI and pain may be worthwhile to prevent a vicious cycle.