Linking sensory experience to bodily states in the insular cortex.

The brain must learn to associate sensory experiences with delayed physiological consequences in order to generate adaptive behavior. The insular cortex is uniquely positioned to support this function, integrating gustatory, visceral, immune, pain, affective, and metabolic information into representations of bodily states. In this review, we examine evidence, primarily from mouse and rat studies and with reference to human work, that insular circuits couple external cues to predicted bodily states. We focus on conditioned taste aversion and conditioned immune responses as complementary models of this computation, in which initially neutral sensory stimuli acquire the ability to evoke learned behavioral or physiological responses despite substantial temporal delays. We discuss how anterior and posterior insular circuits, projection-specific plasticity, inhibitory gating, and molecular mechanisms contribute to the encoding, updating, and retrieval of these associations. This framework positions the insula as a state-dependent hub, generating and regulating learned predictions about the body's future physiological states and needs.