In a new preprint published on bioRxiv, we show that hippocampal sharp-wave ripples may not be needed for acquiring new place-reward associations in a familiar task setting.
Short-term memory on a time scale of seconds to minutes is required to successfully perform day-to-day tasks, for example when engaging in a meaningful conversation. It has been hypothesized that hippocampal replay could support short-term memory, but definitive causal evidence that challenges or confirms this model has been missing.
In a new study, PhD student Lies Deceuninck performed a set of experiments to collecting this causal evidence in behaving rats that perform spatial memory tasks in which the general rule was learned before but the particular elements of how to apply the rule changed from day to day. While rats acquired and executed the tasks, Lies detected signatures of hippocampal replay and immediately disrupted any further activity using an mild electrical shock to the brain. Rats readily learned the task rules and specific disruption of the replay events did not affect task performance or other behavioral measures in any of the tasks. These results show indicate that awake replay does not contribute to short-term spatial memory.
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Awake hippocampal replay is not required for short-term memory
Deceuninck and Kloosterman (2022) bioRxiv 2022.11.03.514989
