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This article is part of the supplement: Sixteenth Annual Computational Neuroscience Meeting: CNS*2007

Open Access Poster presentation

Computational model of a modulatory cell type in the feeding network of the snail, Lymnaea stagnalis

Dimitris V Vavoulis12*, Eugeny S Nikitin2, Jianfeng Feng1, Paul R Benjamin2 and György Kemenes2

Author Affiliations

1 Ctr. for Scientific Computing, University of Warwick, Coventry, UK

2 Sussex Ctr. for Neuroscience, University of Sussex, Brighton, UK

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BMC Neuroscience 2007, 8(Suppl 2):P113  doi:10.1186/1471-2202-8-S2-P113


The electronic version of this article is the complete one and can be found online at:


Published:6 July 2007

© 2007 Vavoulis et al; licensee BioMed Central Ltd.

Introduction

Realistic mathematical models of single neurons are significant in assessing the contribution of specific ionic conductances to neuronal excitability. This study presents a detailed computational model of the Cerebral Giant Cells (CGCs), a pair of serotonergic neurons in the feeding network of Lymnaea stagnalis, which are critical for the expression of motor behaviour (feeding) and the formation of long-term memory.

Methods

First, we fitted a single-compartment, Hodgkin-Huxley model of the CGCs to two-electrode voltage- and current-clamp data [1] using a combination of linear and non-linear least-square fitting techniques. Then, we selectively blocked each ionic current to assess its role in the model, thus mimicking the application of pharmacological agents in the biological neuron.

Results

The model replicates accurately the shape of the action potentials and the tonic firing (~0.74 Hz) of the biological neuron (Fig. 1A). A persistent sodium current INaP and a transient low-threshold calcium current ILVA keep the neuron spontaneously active (Fig. 1Bi, ii). A transient potassium current IA regulates the interspike interval, while a transient high-threshold calcium current IHVA increases the duration of each spike (Fig. 1Biii, iv). Transient sodium and delayed rectifier potassium currents are responsible for the depolarizing and repolarizing phases of the action potential, as in the classical Hodgkin-Huxley model. The available experimental data [1] are in agreement with these conclusions.

thumbnailFigure 1. Overview of the CGCs model and the contribution of specific currents to neuronal excitability. In A, the model has been shifted to the right by 2 msec compared to the biological action potential.

Conclusion

The model we have developed here provides an accurate description of the CGCs at the biophysical level and it is a useful tool for studying the electrical properties of these important modulatory neurons.

Acknowledgements

This research was supported by EPSRC and BBSRC, United Kingdom

References

  1. Staras K, Gyori J, Kemenes G: Voltage-gated ionic currents in an identified modulatory cell type controlling molluscan feeding.

    Eur J Neurosci 2002, 15:109-119. PubMed Abstract | Publisher Full Text OpenURL