Pain
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Forebrain medial septum region facilitates nociception in a rat formalin model of inflammatory pain.
The medial septum is anatomically and functionally linked to the hippocampus, a region implicated in nociception. However, the role of medial septum in nociception remains unclear. To investigate the role of the region in nociception in rats, muscimol, a GABA agonist, or zolpidem, a positive allosteric modulator of GABA(A) receptors, was microinjected into medial septum to attenuate the activity of neurons in the region. ⋯ The reduction was accompanied by a decrease in formalin-induced expression of spinal c-Fos protein that serves as an index of spinal nociceptive processing. The drug effects on nociceptive behaviors were without overt sedation and were distinct from the effects observed after septal lateral microinjections. Taken together, these findings suggest that the activation of medial septum is pro-nociceptive and facilitates aspects of central neural processing underlying nociception.
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Knowledge about functional ability, including activities of daily living (ADL), in patients with chronic widespread pain (CWP) and fibromyalgia (FMS) is largely based on self-report. The purpose of this study was to assess functional ability by using standardised, observation-based assessment of ADL performance and to examine the relationship between self-reported and observation-based measures of disability. A total of 257 women with CWP, 199 (77%) fulfilling the American College of Rheumatology tender point criteria for FMS, were evaluated with the Assessment of Motor and Process Skills (AMPS), an observation-based assessment providing linear measures of ADL motor and ADL process skill ability (unit: logits). ⋯ Only weak to moderate correlations between self-reported functional ability and observation-based AMPS ability measures were observed. The results of the study support the notion of considerable performance difficulties in women with CWP. The everyday life problems are substantial and place the individual at risk of need of support for community living.
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Current fear-avoidance models consider fear of pain as a key factor in the development of chronic musculoskeletal pain. Generally, the idea is that by virtue of the formation of associations or acquired propositional knowledge about the relation between neutral movements and pain, these movements may signal pain, and hence start to elicit defensive fear responses (eg, avoidance behavior). This assumption has never been investigated experimentally. ⋯ Participants were slower initiating a CS+ movement than a CS- movement, while response latencies to CSs in the control condition did not differ. These data support the acquisition of fear of movement-related pain by associative learning. Results are discussed in the broader context of the acquisition of pain-related fear in patients with musculoskeletal pain.