Volume 10 Supplement 1

Eighteenth Annual Computational Neuroscience Meeting: CNS*2009

Open Access

Spiking neural network models for memorizing sequences with forward and backward recall

BMC Neuroscience200910(Suppl 1):P211

DOI: 10.1186/1471-2202-10-S1-P211

Published: 13 July 2009

Introduction

It has been reported that when a rat reaches the end of a track, the hippocampal place cells, which spike sequentially during the run, can generate spikes in a short time window in the reverse order [1, 2]. Also, a forward replay has been recorded from the place cells in a short time interval prior to the run [2]. A recently published model [3] uses phases in the theta cycle to code different locations of the rat. A disadvantage of such an approach is that a frequency of the theta rhythm changes in a wide range and it is not clear whether the phase coding can be reliable under condition of the variable theta-frequency. Here, we present an oscillatory neural network model that can memorize sequences by adapting their synaptic weights during the memorization period. The model includes Hodgkin-Huxley type spiking elements arranged in small groups with excitatory and inhibitory connections. These groups can generate a rhythmic activity in the theta range. Excitatory elements in different groups are coupled by plastic excitatory connections. We propose that each group of rhythmic elements includes two subgroups of excitatory neurons. For the first sub-group, the modification of inter-group excitatory connections is according to the Spike Timing Dependent Plasticity (STDP) learning rule and for the second group the modification is according to the anti-STDP learning rule [3, 4]. Also, these learning rules are adjusted to the cycles of the theta rhythm. This approach allows us to memorize locations in the track during the running stage and replay them in forward order by the first sub-network and in the reverse order by the second sub-network (Figure 1). To initiate forward (backward replay we use a group of neurons corresponding to the beginning (end) of the track. In both cases the duration of replay is short and takes one cycle of the theta rhythm, in accordance with experimental results [1, 2].
https://static-content.springer.com/image/art%3A10.1186%2F1471-2202-10-S1-P211/MediaObjects/12868_2009_Article_1396_Fig1_HTML.jpg
Figure 1

Simulations show the memorizing of four activity patterns corresponding to a sequence of four rat positions along the track. Each pattern contains five groups of interactive excitatory and inhibitory neurons. The right part corresponding the time window of 200 msec shows the backward recall initiated by the activity pattern corresponding to the end of the track.

Declarations

Acknowledgements

This work is supported by UK EPSRC (Grant EP/D036364/1).

Authors’ Affiliations

(1)
Centre for Theoretical and Computational Neuroscience, University of Plymouth

References

  1. Foster DJ, Wilson MA: Reverse replay of behavioural sequences in hippocampal place cells during the awake state. Nature. 2006, 440: 680-683. 10.1038/nature04587.PubMedView ArticleGoogle Scholar
  2. Diba K, Buzsaki G: Forward and reverse hippocampal place-cell sequences during ripples. Nature Neuroscience. 2007, 10: 1241-1242. 10.1038/nn1961.PubMed CentralPubMedView ArticleGoogle Scholar
  3. Koene RA, Hasselmo ME: Reversed and forward buffering of behavioural spike sequences enables retrospective and prospective retrieval in hippocampal regions CA3 and CA1. Neural Networks. 2008, 21: 276-288. 10.1016/j.neunet.2007.12.029.PubMed CentralPubMedView ArticleGoogle Scholar
  4. Han VZ, Grant K, Bell CC: Reversible associative depression and nonassociative potentiation at a parallel fiber synapse. Neuron. 2000, 27: 611-622. 10.1016/S0896-6273(00)00070-2.PubMedView ArticleGoogle Scholar
  5. Rumsey CC, Abbott LF: Synaptic equalization by anti-STDP. Neurocomputing. 2004, 58–60: 359-364. 10.1016/j.neucom.2004.01.067.View ArticleGoogle Scholar

Copyright

© Chik and Borisyuk; licensee BioMed Central Ltd. 2009

This article is published under license to BioMed Central Ltd.

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