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Authors & Affiliations
Dominic Kargl, Wulf Haubensak
Abstract
Affective responses involve assessing the value of environmental cues signaling potential threats or rewards. However, when encountering novel cues, their affective value is uncertain. To overcome this uncertainty, the brain likely creates abstract representations of the environment, linking external stimuli with internal bodily states. However, the exact mechanisms underlying the formation of these affective models remain largely unknown. The insula, known as the primary interoceptive cortex, is a promising area where the associations between environmental cues (conditioned stimuli, CS) and bodily responses (unconditioned stimuli, US) in affective learning may occur. By recording the activity in the associative anterior (aIC) and sensory posterior insular cortex (pIC) during affective learning in mice, we identified distinct tuning of IC subregions to CS and US upon learning. Activity dynamics in the aIC indicate a step-wise process, which concludes with the recruitment of neurons associated with primary rewards and punishments into the CS response. Conversely, US-related activity was dominant in the pIC. Moreover, dual-site recordings reveal that successful learning is accompanied by top-down communication from aIC to pIC, indicating a performance-linked intra-insular hierarchy. In summary, we show that the anticipation of a US triggered by a CS may recreate aspects of the US's affective value in the aIC, while directional communication to the US-tuned pIC might signify a hallmark of an affective experience.