http://www.nitrc.org/forum/forum.php?forum_id=6338 <table border="0" width="100%"><tr><td align="left"/></tr></table> <p><b>Distinct BOLD fMRI Responses of Capsaicin-Induced Thermal Sensation Reveal Pain-Related Brain Activation in Nonhuman Primates.</b></p> <p>PLoS One. 2016;11(6):e0156805</p> <p>Authors: Asad AB, Seah S, Baumgartner R, Feng D, Jensen A, Manigbas E, Henry B, Houghton A, Evelhoch JL, Derbyshire SW, Chin CL</p> <p>Abstract<br/> BACKGROUND: Approximately 20% of the adult population suffer from chronic pain that is not adequately treated by current therapies, highlighting a great need for improved treatment options. To develop effective analgesics, experimental human and animal models of pain are critical. Topically/intra-dermally applied capsaicin induces hyperalgesia and allodynia to thermal and tactile stimuli that mimics chronic pain and is a useful translation from preclinical research to clinical investigation. Many behavioral and self-report studies of pain have exploited the use of the capsaicin pain model, but objective biomarker correlates of the capsaicin augmented nociceptive response in nonhuman primates remains to be explored.<br/> METHODOLOGY: Here we establish an aversive capsaicin-induced fMRI model using non-noxious heat stimuli in Cynomolgus monkeys (n = 8). BOLD fMRI data were collected during thermal challenge (ON:20 s/42°C; OFF:40 s/35°C, 4-cycle) at baseline and 30 min post-capsaicin (0.1 mg, topical, forearm) application. Tail withdrawal behavioral studies were also conducted in the same animals using 42°C or 48°C water bath pre- and post- capsaicin application (0.1 mg, subcutaneous, tail).<br/> PRINCIPAL FINDINGS: Group comparisons between pre- and post-capsaicin application revealed significant BOLD signal increases in brain regions associated with the 'pain matrix', including somatosensory, frontal, and cingulate cortices, as well as the cerebellum (paired t-test, p&lt;0.02, n = 8), while no significant change was found after the vehicle application. The tail withdrawal behavioral study demonstrated a significant main effect of temperature and a trend towards capsaicin induced reduction of latency at both temperatures.<br/> CONCLUSIONS: These findings provide insights into the specific brain regions involved with aversive, 'pain-like', responses in a nonhuman primate model. Future studies may employ both behavioral and fMRI measures as translational biomarkers to gain deeper understanding of pain processing and evaluate the preclinical efficacy of novel analgesics.<br/> </p><p>PMID: 27309348 [PubMed - as supplied by publisher]</p> en-us Copyright 2000-2026 NITRC OSI Tue, 05 May 2026 1:04:54 GMT http://blogs.law.harvard.edu/tech/rss NITRC RSS generator