Memory replay in balanced recurrent networks

PLoS Comput Biol. 2017 Jan 30;13(1):e1005359. doi: 10.1371/journal.pcbi.1005359. eCollection 2017 Jan.

Abstract

Complex patterns of neural activity appear during up-states in the neocortex and sharp waves in the hippocampus, including sequences that resemble those during prior behavioral experience. The mechanisms underlying this replay are not well understood. How can small synaptic footprints engraved by experience control large-scale network activity during memory retrieval and consolidation? We hypothesize that sparse and weak synaptic connectivity between Hebbian assemblies are boosted by pre-existing recurrent connectivity within them. To investigate this idea, we connect sequences of assemblies in randomly connected spiking neuronal networks with a balance of excitation and inhibition. Simulations and analytical calculations show that recurrent connections within assemblies allow for a fast amplification of signals that indeed reduces the required number of inter-assembly connections. Replay can be evoked by small sensory-like cues or emerge spontaneously by activity fluctuations. Global-potentially neuromodulatory-alterations of neuronal excitability can switch between network states that favor retrieval and consolidation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / physiology*
  • Computer Simulation
  • Feedback, Physiological / physiology
  • Humans
  • Mental Recall / physiology*
  • Models, Neurological*
  • Nerve Net / physiology
  • Neuronal Plasticity / physiology*
  • Synapses / physiology*
  • Synaptic Transmission / physiology*

Grant support

This work was supported by: Bundesministerium für Bildung und Forschung: 01GQ1001A, Bundesministerium für Bildung und Forschung: 01GQ1201 for HS, Bundesministerium für Bildung und Forschung: 01GQ0972 for RK, Deutsche Forschungsgemeinschaft: GRK1589/1, and Deutsche Forschungsgemeinschaft KE 788/3-1 for RK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.