Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States; Departments of Physiology and Psychiatry, University of California, San Francisco, San Francisco, United States; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
Departments of Physiology and Psychiatry, University of California, San Francisco, San Francisco, United States; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
Michael E Coulter
Departments of Physiology and Psychiatry, University of California, San Francisco, San Francisco, United States; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States; Departments of Physiology and Psychiatry, University of California, San Francisco, San Francisco, United States; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
Representations related to past experiences play a critical role in memory and decision-making processes. The rat hippocampus expresses these types of representations during sharp-wave ripple (SWR) events, and previous work identified a minority of SWRs that contain ‘replay’ of spatial trajectories at ∼20x the movement speed of the animal. Efforts to understand replay typically make multiple assumptions about which events to examine and what sorts of representations constitute replay. We therefore lack a clear understanding of both the prevalence and the range of representational dynamics associated with replay. Here, we develop a state space model that uses a combination of movement dynamics of different speeds to capture the spatial content and time evolution of replay during SWRs. Using this model, we find that the large majority of replay events contain spatially coherent, interpretable content. Furthermore, many events progress at real-world, rather than accelerated, movement speeds, consistent with actual experiences.
