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Dynamics of a network of excitatory and inhibitory neurons induced by depolarization block

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One of the main findings is that the excitatory neurons exhibit runaway excitation as the inhibitory neurons enter long-lasting depolarization block... 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... 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... We test the predictions of Wilson-Cowan model with a network of Morris-Lecar (ML) neurons... We find that the bistable state is present in the ML network, where the inhibitory neuron's firing rate peaks just before entering depolarization block (Figure 1A)... This type of network dynamics has been reported in... Tristability can also be observed in a ML network when the external input to the inhibitory population is reduced... The transition dynamics of the active state can be oscillatory (Figures 1B and 1C) or monotonic (data not shown) depending on the synaptic time constants as predicted by the Wilson-Cowan model... Hysteresis is observed at the transitions between different states (Figures 1A and 1B), providing evidence that the emergence of three states is a network phenomenon.

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(A,B) Firing rates of excitatory (blue) and inhibitory (red) neurons. Current injection to the excitatory neurons is increased and decreased slowly as shown by the dotted lines. The network is bistable in (A) and tristable in (B). Note that the network can be in different states for the same current input, indicating hysteresis. (C) Same network parameters as in (B) but current injection to the excitatory neurons is constant to demonstrate that the network activity can be oscillatory during the active state.
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Figure 1: (A,B) Firing rates of excitatory (blue) and inhibitory (red) neurons. Current injection to the excitatory neurons is increased and decreased slowly as shown by the dotted lines. The network is bistable in (A) and tristable in (B). Note that the network can be in different states for the same current input, indicating hysteresis. (C) Same network parameters as in (B) but current injection to the excitatory neurons is constant to demonstrate that the network activity can be oscillatory during the active state.

Mentions: We test the predictions of Wilson-Cowan model with a network of Morris-Lecar (ML) neurons. We find that the bistable state is present in the ML network, where the inhibitory neuron's firing rate peaks just before entering depolarization block (Figure 1A). This type of network dynamics has been reported in [1]. Tristability can also be observed in a ML network when the external input to the inhibitory population is reduced. The transition dynamics of the active state can be oscillatory (Figures 1B and 1C) or monotonic (data not shown) depending on the synaptic time constants as predicted by the Wilson-Cowan model. Hysteresis is observed at the transitions between different states (Figures 1A and 1B), providing evidence that the emergence of three states is a network phenomenon.


Dynamics of a network of excitatory and inhibitory neurons induced by depolarization block
(A,B) Firing rates of excitatory (blue) and inhibitory (red) neurons. Current injection to the excitatory neurons is increased and decreased slowly as shown by the dotted lines. The network is bistable in (A) and tristable in (B). Note that the network can be in different states for the same current input, indicating hysteresis. (C) Same network parameters as in (B) but current injection to the excitatory neurons is constant to demonstrate that the network activity can be oscillatory during the active state.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4126555&req=5

Figure 1: (A,B) Firing rates of excitatory (blue) and inhibitory (red) neurons. Current injection to the excitatory neurons is increased and decreased slowly as shown by the dotted lines. The network is bistable in (A) and tristable in (B). Note that the network can be in different states for the same current input, indicating hysteresis. (C) Same network parameters as in (B) but current injection to the excitatory neurons is constant to demonstrate that the network activity can be oscillatory during the active state.
Mentions: We test the predictions of Wilson-Cowan model with a network of Morris-Lecar (ML) neurons. We find that the bistable state is present in the ML network, where the inhibitory neuron's firing rate peaks just before entering depolarization block (Figure 1A). This type of network dynamics has been reported in [1]. Tristability can also be observed in a ML network when the external input to the inhibitory population is reduced. The transition dynamics of the active state can be oscillatory (Figures 1B and 1C) or monotonic (data not shown) depending on the synaptic time constants as predicted by the Wilson-Cowan model. Hysteresis is observed at the transitions between different states (Figures 1A and 1B), providing evidence that the emergence of three states is a network phenomenon.

View Article: PubMed Central - HTML

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

One of the main findings is that the excitatory neurons exhibit runaway excitation as the inhibitory neurons enter long-lasting depolarization block... 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... 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... We test the predictions of Wilson-Cowan model with a network of Morris-Lecar (ML) neurons... We find that the bistable state is present in the ML network, where the inhibitory neuron's firing rate peaks just before entering depolarization block (Figure 1A)... This type of network dynamics has been reported in... Tristability can also be observed in a ML network when the external input to the inhibitory population is reduced... The transition dynamics of the active state can be oscillatory (Figures 1B and 1C) or monotonic (data not shown) depending on the synaptic time constants as predicted by the Wilson-Cowan model... Hysteresis is observed at the transitions between different states (Figures 1A and 1B), providing evidence that the emergence of three states is a network phenomenon.

No MeSH data available.