Neuroreport
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We analyzed, with a new imaging technique, the rapid axon reflex flare responses in human skin upon transcutaneous delivery of electrical stimuli at 1, 5, 10 and 50 Hz in single bursts of five pulses each. Two-dimensional perfusion images covering an area of 8 x 8 cm(2) were captured at 25 Hz and their averages saved at 0.5 Hz. ⋯ Maximum flare responses developed at 5 Hz, whereas pain ratings increased with stimulation frequency. The highest neuropeptide release at 5 Hz correlates to the discharge characteristics of mechanoinsensitive C-fibers, whereas the maximum pain intensity at 50 Hz may be attributed to the activation of A-delta fibers.
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The development of human social cognition has allowed interactions with other species and the formation of a cooperative multi-species society. This feature posited keen attention on the following question: is heterospecific social cognition represented in the same brain areas as conspecific social cognition? Here we investigated brain activity accompanying the facial recognition of familiar humans and of companion dogs, both of whom had real social interactions with participants. The rostroventral anterior cingulate cortex responded to both species whereas the caudal anterior cingulate cortex was sensitive only to familiar humans. Social cognition processes may be dual-layered: the rostroventral anterior cingulate cortex is associated with fundamental and intuitive aspects, whereas the caudal anterior cingulate cortex is concerned with the analysis of complex social interactions.
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Randomized Controlled Trial Clinical Trial
Placebo analgesia is not due to compliance or habituation: EEG and behavioural evidence.
This study was designed to resolve whether experimental placebo responses are due to either increased compliance or habituation. We stimulated both forearms and recorded laser-evoked potentials from 18 healthy volunteers treated on one arm with a sham analgesic cream and an inactive cream on the other (treatment group), and 13 volunteers with an inactive cream on both arms (controls). ⋯ The control group showed no evidence of habituation to the laser stimulus. The results indicate that the reduction in pain during experimental placebo response is unlikely to be due to sensory habituation or compliance with the experimental instructions.
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It is unclear whether shorter wave latencies of middle-latency-auditory-evoked-potentials may be associated to cognitive function other than nondeclarative memory. We investigated the presence of declarative, nondeclarative and dreaming memory in propofol-anaesthetized patients and any relationship to intraoperatively registered middle-latency-auditory-evoked-potentials. An audiotape containing one of two stories was presented to patients during anaesthesia. ⋯ Declarative and nondeclarative memories for intraoperative listening were assessed 24 h after awakening without pointing out positive findings. Six patients who reported dream recall showed an intraoperative Pa latency less than that of patients who were unable to remember any dreams (P<0.001). A high responsiveness degree of primary cortex was associated to dream recall formation during anaesthesia.
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It is known that interleukin-1beta facilitates pain, but the mechanisms of this are not understood. This study investigated the role of interleukin-1beta in the expression of Fos, a marker of neuronal activation, and hyperalgesia caused by injecting complete Freund's adjuvant into one hind paw of the rat. ⋯ Paw withdrawal latency was used to assess hyperalgesia. The findings were that interleukin-1ra inhibited inflammation-induced Fos expression and hyperalgesia, which suggests that endogenous interleukin-1beta facilitates transmission of noxious messages at the spinal level by processes involving an enhanced Fos expression.