Ottawa Researchers Discover Serotonin's Role as a 'Prospective Value Code' in Brain, Influencing Decision-Making

A new study from the University of Ottawa, published in *Nature* (2025), reveals that serotonin acts as a 'prospective code for value' in the brain. This influences decision-making by representing the potential value of future rewards. Researchers, including Dr. Richard Naud, found that serotonin neurons activate in anticipation of future outcomes, not just immediate rewards. This 'prospective value' signal helps the brain evaluate potential actions in dynamic environments. The discovery offers a new perspective of serotonin's multifaceted role beyond simple pleasure responses, impacting mood regulation, learning, and motivated behavior. The study began with simulations by Emerson Harkin, who observed serotonin neurons responding to environmental changes signaling imminent rewards. Future research will explore how the brain interprets serotonin's messages, potentially linking neuroscience and artificial intelligence. This work highlights the complexity of serotonin's functions and its integral role in shaping human experiences.