McGill University Study Reveals Hippocampus Predicts Rewards, Not Just Stores Memories

Researchers at McGill University’s Brandon Lab have overturned a long-held assumption about the hippocampus, revealing the brain’s memory centre doesn’t just store the past – it actively predicts rewards. Published January 29, 2026, in Nature, the preclinical study used advanced imaging techniques to track brain activity in mice, demonstrating a structured reorganization of memories as animals learned a task. “The hippocampus is often described as the brain’s internal model of the world,” explains senior author Mark Brandon, Associate Professor in McGill’s Department of Psychiatry, “What we are seeing is that this model is not static; it is updated day by day as the brain learns from prediction errors.” This discovery offers a new framework for understanding learning and could unlock critical insights into the early stages of Alzheimer’s disease, where decision-making and learning are often impaired.

Hippocampal Neural Shifts Predict Rewards, Not Just Store Memories

Researchers at the Brandon Lab at McGill University, collaborating with Harvard University, have revealed a dynamic function of the hippocampus beyond simple memory storage—predicting future rewards. Published in Nature on January 29, 2026, the study demonstrates the brain region actively reorganizes memories to anticipate outcomes, a previously unobserved learning process. The team tracked neural activity in mice learning a task, utilizing novel imaging techniques allowing weeks-long observation of cellular changes.

The research challenged the assumption that shifts in hippocampal brain activity were random, instead proving they are structured and predictive. “What we found was surprising,” said Brandon, noting that neural activity initially peaking at reward delivery gradually shifted before the reward was received. This suggests the hippocampus supports a more complex form of reward learning than previously understood, building upon the principles demonstrated by Ivan Pavlov’s earlier work. Importantly, this predictive capacity offers a new lens through which to examine the early cognitive deficits seen in Alzheimer’s disease, potentially illuminating pathways for future restoration efforts.

Novel Brain Imaging Tracks Weeks-Long Neuronal Activity Changes

This innovation, first utilized in Canada by the Brandon Lab founded in 2015, allowed scientists to observe how the brain’s memory center adapts to predictable rewards in mice—tracking neuronal “glow” over extended periods. The team discovered that initial neural peaks coinciding with reward delivery gradually moved earlier, ultimately occurring before the reward was received, demonstrating the hippocampus isn’t merely storing memories but actively predicting outcomes. This structured reorganization challenges the long-held assumption of randomness in hippocampal activity shifts and offers a new perspective on sophisticated reward learning, moving beyond the simple cue-reward associations established by Pavlov’s experiments.

Predictive Hippocampus Dysfunction Linked to Early Alzheimer’s Impact

This predictive capacity, exceeding simpler reward associations demonstrated by Pavlov, positions the hippocampus as a sophisticated learning center integrating memory and context. The research suggests Alzheimer’s disease impacts this predictive function early on, explaining difficulties with learning and decision-making observed in patients. The Brandon Lab, founded in 2015, hopes this work will illuminate how this predictive signal may fail and be restored, potentially leading to new therapeutic strategies.