Our preliminary results indicate that the primary differences between the relative power over time of natural awakenings and pain-induced awakenings are that 1) in beta, gamma, and high gamma frequency bands, the pain-induced awakenings show lower increase in relative

There is currently no objective biomarker for pain. In this study, we used an optogenetic approach to activate nociceptors in mice and trigger awakenings within milliseconds while recording their electroencephalogram (EEG). We performed spectral analyses to test if these pain-induced awakenings have a specific EEG marker compared to spontaneous awakenings. In contrast to natural awakenings, we found that they have lower beta, gamma, and high gamma relative power during an awakening, but that the relative power in gamma and high gamma bands remain elevated for longer when transitioning back to sleep. The increased time to return to baseline power may help explain why chronic pain patients suffer from poor sleep quality and daytime fatigue. Clinical Relevance— Identifying an EEG marker of pain-induced awakenings will allow objective quantification of pain in rodents, which will facilitate mechanistic studies and preclinical research to develop new analgesics.