Pain
-
Current knowledge on pain-related cerebral networks has relied so far on stimulus-induced brain responses, but not on the analysis of brain activity during spontaneous pain attacks. In this case report, correlation between intracerebral field potentials and online sensations during spontaneously painful epileptic seizures suggests a crucial role of the insula in the development of subjective pain. Attacks originated from a very limited dysplasia located in the posterior third of the right insula and propagated to other areas of the pain matrix, including the parietal operculum and the midcingulate gyrus. ⋯ Stimulation of the insula, but not of other pain matrix regions, induced pain identical to that of seizures. After thermocoagulation of the insular epileptic focus, a short, transient exacerbation of seizures with same painful features but different location was observed before a long-lasting and complete remission of the attacks. Although these preliminary data need to be confirmed, they strongly suggest that if the full pain experience involves the pain matrix network, the posterior insula seems to play a leading role in the triggering of this network and the resulting emergence of subjective pain experience.
-
Facial expression is one of the most relevant nonverbal behaviors in the communication of pain. However, little is known about brain processing of pain expressions in comparison with other affective facial expressions. The present experiment aimed to examine the effects of pain expression intensity on affective ratings and brain dynamics by recording electroencephalography (EEG) from 20 female healthy volunteers 18-24 years of age. ⋯ EEG results further showed that facial expressions of pain elicited more enhanced amplitudes of the visual evoked potentials than anger and neutral faces in the latency between 350 and 550 milliseconds after stimulus onset; whereas anger faces elicited greater P200 amplitudes than pain and neutral faces. In addition, more increased theta activity in the latency of 200 to 400 milliseconds after stimulus onset was observed to high-intense as compared with low-intense facial expressions. These findings indicate that brain activity elicited by affective faces is modulated by the intensity of facial expressions and suggest the involvement of different brain mechanisms during the processing and recognition of facial expressions of pain and anger in healthy volunteers.
-
Editorial Comment Review
Acupuncture's claims punctured: not proven effective for pain, not harmless.
-
Musculoskeletal pain is common among adolescents, but little is known about the factors that affect seeking health care for the problem. We examined the care-seeking pattern among adolescents reporting musculoskeletal pain. The study consisted of adolescents aged 16 years from the 1986 Northern Finland Birth Cohort who responded to a mailed questionnaire in 2001 and reported musculoskeletal pain over the preceding 6 months (n=5052). ⋯ Reporting pain in other anatomical areas decreased the likelihood of seeking care for pain among both genders. In conclusion, relatively few adolescents with musculoskeletal pain had consulted a health professional for the problem. Being physically active (trauma), participating in organized sport (accessibility of care), and having other health problems may explain why an adolescent seeks care for musculoskeletal pain.
-
Although both a loss of spinal inhibitory neurotransmission and the involvement of oxidative stress have been regarded as important mechanisms in the pathogenesis of pain, the relationship between these 2 mechanisms has not been studied. To determine whether reactive oxygen species (ROS) involvement in pain mechanisms is related to the diminished inhibitory transmission in the substantia gelatinosa (SG) of the spinal dorsal horn, behavioral studies and whole-cell recordings were performed in FVB/NJ mice. Neuropathic pain was induced by a tight ligation of the L5 spinal nerve (SNL). ⋯ In SNL mice, mIPSC frequency in SG neurons was significantly reduced as compared with that of normal mice, which was restored by PBN. The antihyperalgesic effect of PBN on mechanical hyperalgesia was attenuated by intrathecal bicuculline, a GABA(A) receptor blocker. Our results indicate that the increased ROS in spinal cord may induce pain by reducing GABA inhibitory influence on SG neurons that are involved in pain transmission.