Tau protein essential for forming long-lasting memories, mouse study finds

A protein best known for its role in Alzheimer's disease is also essential for creating memories that last, according to a mouse study led by Flinders University and published in Nature Communications. Researchers found that tau helps organize and stabilize memories so they can be retained over time, but it is not needed for learning something new or remembering it shortly afterward. The team studied "remote memory" in mice, which refers to memories recalled days or weeks after an experience. They discovered that tau is active during a critical stage of memory formation, helping determine which specialized brain cells called engram cells are recruited to preserve an experience. Tau also reduces background neural activity during memory formation, allowing only a specific group of cells to become part of a memory trace. The study showed that controlled, low-level phosphorylation of tau is a normal and essential part of healthy brain function, even though abnormal tau phosphorylation is a hallmark of Alzheimer's disease. In the absence of tau, memory traces still existed and could be recovered by directly stimulating engram cells, suggesting tau is not required to store memories but to connect natural cues with the ability to recall them. When disease-associated forms of tau were present during learning, they disrupted the creation of new memories; when they appeared after memories had formed, they interfered with retrieval. Senior author Associate Professor Arne Ittner said the findings help explain why people with dementia may still learn new information initially yet struggle to retain it. Because the research was conducted in mice, the findings cannot be directly applied to human memory or Alzheimer's disease, but they offer clues that could shape future dementia research and treatment strategies.