ArticleNeural coding of nociceptive stimuli—from rat spinal neurones to human perceptionSikandar, Shafaq*; Ronga, Irene; Iannetti, Gian Domenico; Dickenson, Anthony H.Author Information Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article. Department of Neuroscience, Physiology and Pharmacology, University College London, United Kingdom *Corresponding author. Address: Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom. Tel.: +44 (0) 20 7679 3737. E-mail address: [email protected] Submitted July 31, 2012; revised March 21, 2013; accepted March 29, 2013. Pain: August 2013 - Volume 154 - Issue 8 - p 1263-1273 doi: 10.1016/j.pain.2013.03.041 Buy Metrics Abstract This study used radiant laser pulses to explore the central processing and spatial summation of nociceptive inputs in a novel parallel investigation between rats and humans. Translational studies are key to furthering our understanding of nociceptive signalling and bridging the gaps between molecules and pathways to the patients. This requires use of appropriate preclinical models that accurately depict outcome measures used in humans. Whereas behavioural animal studies classically involve reports related to nociceptive thresholds of, for example, withdrawal, electrophysiological recordings of spinal neurones that receive convergent input from primary afferents permits investigation of suprathreshold events and exploration of the full-range coding of different stimuli. We explored the central processing of nociceptive inputs in a novel parallel investigation between rats and humans. Using radiant laser pulses, we first compared the electrophysiological responses of deep wide dynamic range and superficial nociceptive-specific neurones in the rat dorsal horn with human psychophysics and cortical responses. Secondly, we explored the effects of spatial summation using laser pulses of identical energy and different size. We observed 3 main findings. Firstly, both rodent and human data confirmed that neodymium–yttrium aluminium perovskite laser stimulation is a nociceptive-selective stimulus that never activates Aβ afferents. Secondly, graded laser stimulation elicited similarly graded electrophysiological and behavioural responses in both species. Thirdly, there was a significant degree of spatial summation of laser nociceptive input. The remarkable similarity in rodent and human coding indicates that responses of rat dorsal horn neurones can translate to human nociceptive processing. These findings suggest that recordings of spinal neuronal activity elicited by laser stimuli could be a valuable predictive measure of human pain perception. © 2013 Lippincott Williams & Wilkins, Inc.