A cellular mechanism for system memory consolidation

Abstract

Event Abstract Back to Event A cellular mechanism for system memory consolidation Michiel W. Remme1*, Urs M. Bergmann1, Susanne Schreiber1, Henning Sprekeler1 and Richard Kempter1 1 Humboldt University Berlin, Institute for Theoretical Biology, Germany Declarative memories initially depend on the hippocampus. Over a period of weeks to years, however, these memories become hippocampus-independent through a process called system memory consolidation. The underlying cellular mechanisms are unclear. Here, we suggest a consolidation mechanism, which is based on STDP and a ubiquitous anatomical network motif. As a first step in the memory consolidation process, we consider pyramidal neurons in the hippocampal CA1 area. These cells receive Schaffer collateral (SC) input from the CA3 area at the proximal dendrites, and perforant path (PP) input from entorhinal cortex at the distal dendrites. Both pathways carry sensory information that has been processed by cortical networks and that enters the hippocampus through the entorhinal cortex. Hence, information from entorhinal cortex reaches CA1 cells through an indirect pathway (via CA3 and SC) and a direct pathway (PP). Memories are assumed to be initially stored in the recurrent CA3 network and the SC synapses during the awake, exploratory state. During a subsequent consolidation phase (during slow-wave sleep) SC-dependent memories are partly transferred to the PP synapses. Through mathematical analysis and numerical simulations we show that this consolidation process occurs as a natural result from the combination of (1) STDP at PP synapses and (2) the temporal correlations between SC and PP activities, since the (indirect) SC input is delayed compared to the (direct) PP input by about 5-10 ms. With a detailed compartmental model we then show that the spatial tuning of a CA1 cell is copied from the proximal SC-synaptic inputs to the distal PP-inputs. Next, we repeated the network motif across many levels in a hierarchical network model: each direct connection at one level is part of the indirect pathway of the next level. Analysis and simulations of this hierarchical system demonstrate that memories gradually move from hippocampus into neocortex. Moreover, the memories show power-law forgetting, as seen with psychophysical forgetting functions. Hence, our work proposes a novel mechanism to underlie system memory consolidation, allowing us to bridge spatial scales from single cells to cortical areas, and time scales from milliseconds to years. Acknowledgements Supported by BMBF grants no. 01GQ0901, 01GQ0972, 01GQ1201, 01GQ1001A, DFG grant no. SFB 618 and the Einstein Stiftung Berlin. Keywords: System memory consolidation, Pyramidal neurons, dendritic integration, stdp learning, Hippocampus, Neocortex Conference: 4th NAMASEN Training Workshop - Dendrites 2014, Heraklion, Greece, 1 Jul - 4 Jul, 2014. Presentation Type: Poster presentation Topic: the role of dendrites in complex processes, including learning/memory and neural computations Citation: Remme MW, Bergmann UM, Schreiber S, Sprekeler H and Kempter R (2014). A cellular mechanism for system memory consolidation. Front. Syst. Neurosci. Conference Abstract: 4th NAMASEN Training Workshop - Dendrites 2014. doi: 10.3389/conf.fnsys.2014.05.00010 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: 11 Apr 2014; Published Online: 12 Jun 2014. * Correspondence: Dr. Michiel W Remme, Humboldt University Berlin, Institute for Theoretical Biology, Berlin, 10115, Germany, michiel.remme@hu-berlin.de 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 Michiel W Remme Urs M Bergmann Susanne Schreiber Henning Sprekeler Richard Kempter Google Michiel W Remme Urs M Bergmann Susanne Schreiber Henning Sprekeler Richard Kempter Google Scholar Michiel W Remme Urs M Bergmann Susanne Schreiber Henning Sprekeler Richard Kempter PubMed Michiel W Remme Urs M Bergmann Susanne Schreiber Henning Sprekeler Richard Kempter 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.