Beyond Auditory Relay: Dissecting the Inferior Colliculus’s Role in Sensory Prediction, Cognitive Decision-Making, and Reward Prediction

The Inferior Colliculus (IC) has traditionally been regarded as an important relay in the auditory pathway, primarily involved in relaying auditory information from the brainstem to the thalamus. However, this study uncovers the multifaceted role of the IC in bridging auditory processing, sensory prediction, and reward prediction. Through extracellular recordings in monkeys engaged in a sound duration-based novelty detection task, we observed a "climbing effect" in neuronal firing rates, indicative of an enhanced response over sound sequences linked to sensory prediction rather than reward anticipation. Further exploration revealed a direct correlation between IC neuronal activity and behavioral choices, suggesting its involvement in decision-making processes. Additionally, our findings demonstrate reward prediction errors within the IC, highlighting its complex integration in auditory and reward processing. This research challenges conventional views of the IC, showcasing its integral role in cognitive and sensory processing and emphasizing its importance in integrated brain functions.