European journal of pain : EJP
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Laser-evoked potentials (LEP) were assessed after peripheral nerve block of the lateral femoral cutaneous nerve (LFCN) in healthy volunteers from partially anesthetized skin areas to differentially stimulate mechano-insensitive nociceptors. ⋯ The increase in LEP latency suggests that mechano-insensitive heat-sensitive Aδ nociceptors (MIA, type II) have a slower conduction velocity or higher utilization time than mechano-sensitive type II Aδ nociceptors. Moreover, widely branched, slowly conducting and mechano-insensitive branches of Aδ nociceptors can explain our finding. LEPs in the differentially anesthetized skin provide specific information about a mechanically insensitive but heat-sensitive subpopulation of Aδ nociceptors. These findings support the concept that A-fibre nociceptors exhibit a similar degree of modality specificity as C-fibre nociceptors.
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The spatial precision of expectancy effects on pain is unclear. We hypothesized that expecting nociceptive stimuli at particular skin sites would have an analgesic effect on nociceptive stimuli presented between them (middle zone). ⋯ Expecting a painful stimulus in non-adjacent skin sites has spatially specific effects on pain modulation, but this reflects an interaction between the expected location of stimulation and the actual location. This suggests a more complex connection between somatotopic maps and nociceptive modulation than previously thought; several distinct mechanisms likely contribute.
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Cognitive processes like attentional and interpretation biases have been suggested to play a vital role in the onset and exacerbation of chronic pain. Research consistently supports the occurrence of interpretation bias (IB) in pain patients and healthy individuals high in pain anxiety. Nevertheless, studies on the indirect assessment of IB or the relation between IB and responses to pain are limited. The present studies examined the association between indirect assessed IB and pain anxiety, while Study 2 additionally examined IB as a mediator in the relation between pain anxiety and pain responses. ⋯ Current findings underscore the importance of interpretational processes in the context of physical health threat. Furthermore, the ambiguous word priming task is proposed as a suitable paradigm for further research on the indirect assessment of IB. Nevertheless, further research is warranted to deepen our understanding of IB and its contribution to the experience of (chronic) pain.
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Chronic pelvic pain (CPP) is a high burden for patients and society. It affects 15-24% of women in reproductive age and is an area of high unmet medical need. CPP can be caused by a wide range of visceral diseases such as abdominal infections, gastrointestinal or gynaecological diseases like endometriosis. Despite the high medical need for this condition, pharmacological approaches are hampered by the limited number of available methods for the behavioural evaluation of pain in inflammation-driven animal models of pelvic pain. ⋯ This study described for the first time the use of DWB as a non-subjective and non-reflexive method for the evaluation of inflammatory-driven abdominal pain in a mouse model.