Articles: function.
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Menstrual pain is associated with deficits in central pain processing, yet neuroimaging studies to date have all been limited by focusing on group comparisons of adult women with vs without menstrual pain. This study aimed to investigate the role of the triple network model (TNM) of brain networks in adolescent girls with varied menstrual pain severity ratings. One hundred participants (ages 13-19 years) completed a 6-min resting state functional magnetic resonance imaging (fMRI) scan and rated menstrual pain severity, menstrual pain interference, and cumulative menstrual pain exposure. ⋯ In addition, menstrual pain interference was positively associated with connectivity within the left CEN, whereas connectivity both within the right CEN and between the right CEN and cortical areas outside the network (including the insula) were negatively associated with menstrual pain interference. Cumulative menstrual pain exposure shared a strong negative association with connectivity between the default mode network and other widespread regions associated with large-scale brain networks. These findings support a key role for the involvement of TNM brain networks in menstrual pain characteristics and suggest that alterations in pain processing exist in adolescents with varying levels of menstrual pain.
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The lead symptom of small fibre neuropathy (SFN) is neuropathic pain. Recent functional magnetic resonance imaging (fMRI) studies have indicated central changes in SFN patients of different etiologies. However, less is known about brain functional connectivity during acute pain processing in idiopathic SFN. ⋯ We found increased functional connectivity between SMA and thalamus during painful stimulation in patients with idiopathic SFN. Connectivity correlated significantly with intraepidermal nerve fibre density, suggesting a link between peripheral and central pain processing. Our findings emphasize the importance of investigating functional connectivity changes as a potential feature of SFN.
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We examined de-functionalization and temporal functional recovery of C-nociceptor evoked pain after topical 8% capsaicin applied for 4 consecutive days. ⋯ Sinusoidal electrical stimulation can still activate small diameter axons desensitized to heat after 4 consecutive days of topical 8% capsaicin application and reveals differential temporal functional regeneration of C-nociceptor sub-types. Electrical sinusoidal stimulation may detect such axons that no longer respond to heat stimuli in neuropathic skin.
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Sensory profiling in neuropathic pain using quantitative sensory testing (QST) has not been extended to central neuropathic pain due to spinal cord injury (SCI). This study aims to fill this gap by evaluating sensory profiles in patients with neuropathic SCI pain. ⋯ The evaluation of sensory phenotypes by quantitative sensory testing in central neuropathic pain due to SCI adds a new perspective on sensory phenotypes in comparison to peripheral neuropathic pain. The described thermal and mechanical hyperalgesia combination might represent involvement of the spinothalamic tract. In addition, there was a trend towards older age and longer time since injury in patients with loss of function.
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Motivation can be investigated with the BIS (Behavioural Inhibition System)/BAS (Behavioural Activation System) scale. BAS regulates the motivation to approach goal-oriented outcomes, particularly rewarding stimuli and situations, while BIS regulates escape and avoidance of unpleasant outcomes. Chronic whiplash-associated disorders (WAD) is a heterogenous pain condition with known alterations in motivated behaviour. The study aimed (1) to investigate the relationship between BIS/BAS, and pain and disability with quality of life and psychological measures in chronic WAD; (2) to determine if BIS and/or BAS mediate the relationships between pain, disability, and psychological symptoms and quality of life. ⋯ In line with current theories, we found a large proportion (30%-50%) of patients with whiplash-associated disorders (WAD) showing signs of altered function in the Behavioural Inhibition System (BIS) and Behavioural Activation System (BAS) suggesting altered reward processing and motivation in these patients. While such altered functions showed associations with pain interference, disability and all mental health measures, reward processing could no be demonstrated as a pathogenetically relevant factor in chronic WAD patients.