- Poster presentation
- Open Access
Dynamics of a network of excitatory and inhibitory neurons induced by depolarization block
© Kim and Nykamp; licensee BioMed Central Ltd. 2014
- Published: 21 July 2014
- External Input
- Inhibitory Neuron
- Inhibitory Population
- Phase Plane Analysis
- Seizure State
The balance of excitation and inhibition is important in regulating the network activity. Under pathological conditions the interaction of excitatory and inhibitory neurons can become unbalanced, leading to seizure-like activity in the network. The interplay between excitatory and inhibitory neurons has been studied in rat hippocampal CA1, where spontaneous seizure-like activity was produced by blocking potassium ion channels and decreasing magnesium . One of the main findings is that the excitatory neurons exhibit runaway excitation as the inhibitory neurons enter long-lasting depolarization block.
In this study, we employ a modified Wilson-Cowan (WC) model  to examine the dynamics of an EI network under similar pathological conditions. To model depolarization block, we modified the inhibitory population's activation function so that large input silences the population. Phase plane analysis shows that the network can be in as many as three different states, rest state, active state, and seizure state, where the inhibitory population enters depolarization block in the seizure state. If both populations receive a similar amount of external input, the Wilson-Cowan model predicts that the network is bistable. In this case, the network can be in either the rest state or the seizure state, where the transition to the seizure state occurs as the inhibitory population enters depolarization block. Alternatively, if the external input to the inhibitory population is small, the network can become tristable, where all three state coexist for the same parameters. The network now has to pass the intermediate state (i.e. active state) before it enters the seizure state. Such network transitions can be either oscillatory or monotonic.
- Ziburkus J, Cressman JR, Barreto E, Schiff SJ: Interneuron and pyramidal cell interplay during in vitro seizure-like events. J Neurophy. 2006, 95: 3948-3954. 10.1152/jn.01378.2005.View ArticleGoogle Scholar
- Wilson H, Cowan J: Excitatory and inhibitory interactions in localized populations of model neurons. Biophy J. 1972, 12: 1-22.View ArticleGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.