Codificación dinámica de señales de error de predicción de recompensa en el área tegmental ventral de la paloma...

Reward prediction errors (RPEs) guide learning by comparing expected and obtained outcomes. In mammals, ventral tegmental area (VTA) activity is closely linked to RPE-like signaling, yet how avian VTA dynamics evolve during reinforcement learning remains less well characterized. Here we recorded VTA spiking in pigeons (2 female and 1 male) performing a cue-guided operant task in which a green cue (Cue+) predicted reward contingent on a key peck, whereas a red cue (Cue-) was unrewarded. Using a 16-channel microwire array, we analyzed pooled channel-level multi-unit activity (MUA) aligned to task events. Across sessions, Cue+ trials showed a learning-related redistribution of event-locked modulation: outcome-locked activity was more prominent early in training, while cue-locked modulation became stronger as performance stabilized, consistent with a temporal-difference-like shift of prediction-related signals. Cue- trials were sparse after early learning and showed limited cue-locked modulation in the available dataset. Together, these results provide initial evidence that pigeon VTA pooled MUA exhibits learning-related dynamics consistent with RPE-like processing and support cross-species comparisons of dopaminergic learning signals.Significance Statement This study provides initial evidence that neurons in the pigeon ventral tegmental area (VTA) may encode reward prediction error (RPE) signals during reinforcement learning. The results show that neural activity related to reward gradually shifts toward the predictive cue as learning progresses, consistent with established models in mammals. These findings suggest that the basic neural processes underlying reward-based learning may be shared across vertebrate species and contribute to a broader understanding of comparative learning mechanisms.