The journal of pain : official journal of the American Pain Society
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There is significant heterogeneity in pain outcomes following motor vehicle crashes (MVCs), such that a sizeable portion of individuals develop symptoms of chronic pain months after injury while others recover. Despite variable outcomes, the pathogenesis of chronic pain is currently unclear. Previous neuroimaging work implicates the dorsal anterior cingulate cortex (dACC) in adaptive control of pain, while prior resting state functional magnetic resonance imaging studies find increased functional connectivity (FC) between the dACC and regions involved in pain processing in those with chronic pain. ⋯ Given a relatively small sample size, approximately half of which did not experience chronic pain at 6 months, findings warrant replication. Nevertheless, this study provides preliminary evidence of enhanced dACC connectivity with motor regions and decreased connectivity with pain processing regions as immediate and prospective predictors of pain following MVC. PERSPECTIVE: This article presents evidence of distinct neural vulnerabilities that predict chronic pain in MVC survivors based on whole-brain connectivity with the dorsal anterior cingulate cortex.
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There is evidence from preclinical models of chronic pain and human psychophysical investigations to suggest that alterations in endogenous brainstem pain-modulation circuit functioning are critical for the initiation and/or maintenance of pain. Whilst preclinical models have begun to explore the functioning of this circuitry in chronic pain, little is known about such functioning in humans with chronic pain. The aim of this investigation was to determine whether individuals with chronic non-neuropathic pain, painful temporomandibular disorders (TMD), display alterations in brainstem pain-modulating circuits. ⋯ PERSPECTIVE: Psychophysical studies suggest that brainstem pain-modulation circuits contribute to the maintenance of chronic pain. We report that individuals with painful TMD display altered static and dynamic FC within the brainstem pain-modulation network. Modifying this circuitry may alter an individual's ongoing pain.
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Diagnostic criteria for provoked vestibulodynia (PVD) rely on mucosal pain in the vulvar vestibule, with less emphasis on pain from pelvic floor muscles. It is unknown how psychosocial variables associated with PVD are differentially associated with mucosal versus muscle pain. Analysis of data from the National Vulvodynia Registry (n = 202) revealed several factors associated with increased mucosal pain: pain duration (P = .043), the McGill sensory subscore (P = .0086) and the Gracely pain scale (P< .001). ⋯ Significant differences in the relationship between muscle and mucosal pain for pain duration (P = .005), McGill affective score (P = .001), orgasm (P = .049), change in intercourse frequency (P = .027), and state anxiety (P = .030) suggest the possibility of mucosal or muscle pain predominant PVD subtypes. PERSPECTIVE: Patients with higher pelvic floor muscle pain scores than mucosal pain scores may represent different subgroups or characteristics of patients with provoked vestibulodynia. This research highlights the importance of assessment of the pelvic floor muscles in addition to the cotton swab test of the vestibule.
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Comparative Study
The Time Course of Facial Expression Recognition Using Spatial Frequency Information: Comparing Pain and Core Emotions.
We are able to recognize others' experience of pain from their facial expressions. However, little is known about what makes the recognition of pain possible and whether it is similar or different from core emotions. This study investigated the mechanisms underpinning the recognition of pain expressions, in terms of spatial frequency (SF) information analysis, and compared pain with 2 core emotions (ie, fear and happiness). ⋯ PERSPECTIVE: Two studies explore the perceptual and temporal properties of the decoding of pain facial expressions. At very early stages of attention, the recognition of pain was found to be more difficult than fear and happiness. It suggests that pain is a complex expression, and requires additional time to detect and process.