Spinal cord lamina I neurons receiving dense input from nociceptors, and projecting to the parabrachial area at the ponto-mesencephalic junction form the major ascending pain-related pathway in rodents. Lamina I spinoparabrachial neurons have never been characterised in mice, despite the growing and extensive use of this species to understand the contribution of lamina I spinoparabrachial neurons in chronic pain. The electrophysiological properties of lamina I spinoparabrachial neurons recorded here in the anaesthetized mice are comparable to those of rat or cat, forming a nociceptive and thermoreceptive pathway. It was confirmed "on line" that lamina I spinoparabrachial neurons that normally encode noxious stimuli can receive input from low threshold mechanoreceptors in certain conditions. The present work indicates that the study of lamina I spinoparabrachial neurons in vivo could take advantage of the use of genetically modified mice.