Gut-to-brain interoceptive pathways in emotion-related behaviors

Emotion-related states encompass a wide range of affective and behavioral dimensions, including anxiety, fear, pleasure, and aversion, whereas motivation refers to internal drives that energize goal-directed behaviors such as feeding, reward seeking, or avoidance. These states are thought to arise from the brain's integration of exteroceptive inputs, interoceptive signals reflecting bodily states, and prior experiences. Recent studies have increasingly highlighted the critical role of gut-to-brain communication, particularly vagal and other interoceptive pathways, in shaping emotion-related and motivational behaviors. In parallel, advances in genetic manipulation techniques have enabled the identification of neuronal circuits innervating the gastrointestinal tract and have provided new insights into their links with affective-like behavior. A better understanding of these mechanisms will be essential for elucidating how gastrointestinal-derived signals contribute to emotion-related states and how they are represented and processed in the brain. In this review, we discuss recent advances in gut-to-brain neural pathways, with a particular focus on vagal afferent and interoceptive mechanisms, while also considering spinal afferent pathways and ENS-related mechanisms that may contribute to emotion-related behavioral regulation.