Pain
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Randomized Controlled Trial
Differential neurophysiological correlates of bottom-up and top-down modulations of pain.
The perception of pain is highly variable. It depends on bottom-up-mediated factors like stimulus intensity and top-down-mediated factors like expectations. In the brain, pain is associated with a complex pattern of neuronal responses including evoked potentials and induced responses at alpha and gamma frequencies. ⋯ In contrast, placebo analgesia was associated with changes of evoked potentials, but not of alpha and gamma responses. These findings reveal that pain-related neuronal responses are differentially sensitive to bottom-up and top-down modulations of pain, indicating that they provide complementary information about pain perception. The results further show that pain-induced gamma oscillations do not invariably encode pain perception but may rather represent a marker of sensory processing whose influence on pain perception varies with behavioral context.
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There has been a recent increase in public and professional concern about the prescription of strong prescription opioids for pain. Despite this concern, research to date has been limited because of a number of factors such as small sample sizes, exclusion of people with complex comorbidities, and studies of short duration. The Pain and Opioids IN Treatment is a 2-year prospective cohort study of 1500 people prescribed with pharmaceutical opioids for their chronic pain. ⋯ The younger groups experienced higher levels of pain and pain interference, more mental health and substance use issues, and barriers to treatment, compared with the older group. This study found that the people who have been prescribed strong opioids for chronic pain have very complex demographic and clinical profiles. Major age-related differences in the experiences of pain, coping, mental health, and substance use suggest the necessity of differential approaches to treatment.