THE ROLE OF CORE BODY TEMPERATURE IN THERMAL PERCEPTION AND CORTICAL CELLULAR ENCODING

Our body state has a profound influence in how we feel sensory stimuli. For instance, when core body temperature is elevated, a cool shower feels refreshing, but not when core temperature is low. To support adaptive behaviour and metabolic regulation, the brain must integrate internal physiological signals with external sensory input. The insular cortex has been proposed to function as a ‘sensory-state’ integrator, as it encodes both of internal physiological state and external sensory information. Here, we investigate how core body temperature influences thermal perception and the neuronal encoding of external thermal stimuli. We trained TRPM2-cre mice to report detection of thermal stimuli delivered to their paw in a go/no-go detection paradigm. To induce decreases in body core temperature (~1-5^oC), we chemogenetically manipulated the medial preoptic area (mPOA) of the hypothalamus. Lowering the body temperature selectively reduced the detection of cooling stimuli, while detection of warming or acoustic stimuli was unaffected, indicating a specific alteration in cooling perception. To address the neuronal basis of this, we performed widefield and 2-photon calcium imaging of the posterior insular (pIC) and the forepaw primary somatosensory cortex (fSI) in awake and anaesthetised mice during changes in body temperature. Preliminary analysis suggests that core temperature modulates cortical encoding of thermal stimuli. Together, our results contribute to our understanding of how the nervous system integrates thermoregulation and thermosensation.