Event Abstract Back to Event Reward enhances reactivation of experience in the hippocampus Experiences that lead to salient outcomes are more readily stored in memory. The hippocampus is required for storing memories of the places and events that make up these experiences. Although we might expect that salient outcomes would enhance memory storage, no neural mechanism has been found by which the outcome of an event enhances hippocampal memory formation for that event. Previous studies examining hippocampal responses to different outcomes have generally focused on the presence or absence of food reward. These studies report responses to reward that are similar to responses to other sorts of cues. Thus, there is currently no evidence for a change in hippocampal memory processing as a result of reward. Previous studies focused on place field activity, where hippocampal excitatory cells ('place cells') fire in particular locations in space during active exploration. Place cells are also active during high frequency network oscillations called sharp wave ripples (SWRs), in which sequences of cells active during running are often reactivated. Reactivation is thought to be important for long term memory formation, so we asked whether reward affects reactivation of experience in the hippocampus compared to no reward. We recorded from principal neurons in hippocampal area CA3 while animals learned to switch between two spatial sequences in response to changing reward contingencies. Here we show that hippocampal CA3 principal cells are much more active during SWRs at the end of rewarded as compared to unrewarded trajectories. This increased activation is strongest among cells that have place fields related to the rewarded location. At a population level, SWRs associated with reward preferentially activate pairs of CA3 place cells with overlapping place fields. The result is patterned CA3 activity consistent with the ordered replay of past and future trajectories seen in downstream hippocampal area CA1. These findings establish that information about the presence or the absence of a reward sculpts subsequent memory reactivation in the hippocampus. We propose this enhanced reactivation could be a general mechanism to encode experiences related to salient outcomes. More, generally this repetition of recent experience as a result of reward may help us understand how the hippocampus contributes to reinforcement learning. Conference: Computational and systems neuroscience 2009, Salt Lake City, UT, United States, 26 Feb - 3 Mar, 2009. Presentation Type: Oral Presentation Topic: Oral Presentations Citation: (2009). Reward enhances reactivation of experience in the hippocampus. Front. Syst. Neurosci. Conference Abstract: Computational and systems neuroscience 2009. doi: 10.3389/conf.neuro.06.2009.03.303 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 04 Feb 2009; Published Online: 04 Feb 2009. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Google Google Scholar PubMed Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.