Hippocampal Replay of Extended Experience
During pauses in exploration, ensembles of place cells in the rat hippocampus re-express firing sequences corresponding to recent spatial experience. Such “replay” co-occurs with ripple events: short-lasting (∼50–120 ms), high-frequency (∼200 Hz) oscillations that are associated with increased hippo...
| Main Authors: | , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
Elsevier B.V.
2015
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| Online Access: | http://hdl.handle.net/1721.1/96297 https://orcid.org/0000-0001-7149-3584 |
| Summary: | During pauses in exploration, ensembles of place cells in the rat hippocampus re-express firing sequences corresponding to recent spatial experience. Such “replay” co-occurs with ripple events: short-lasting (∼50–120 ms), high-frequency (∼200 Hz) oscillations that are associated with increased hippocampal-cortical communication. In previous studies, rats exploring small environments showed replay anchored to the rat's current location and compressed in time into a single ripple event. Here, we show, using a neural decoding approach, that firing sequences corresponding to long runs through a large environment are replayed with high fidelity and that such replay can begin at remote locations on the track. Extended replay proceeds at a characteristic virtual speed of ∼8 m/s and remains coherent across trains of ripple events. These results suggest that extended replay is composed of chains of shorter subsequences, which may reflect a strategy for the storage and flexible expression of memories of prolonged experience. |
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