A unified physiological framework of transitions between seizures, status epilepticus and depolarization block at the single neuron level

  title={A unified physiological framework of transitions between seizures, status epilepticus and depolarization block at the single neuron level},
  author={Damien Depannemaecker and Anton I. Ivanov and Davide Lillo and Len Spek and Christophe Bernard and Viktor Jirsa},
The majority of seizures recorded in humans and experimental animal models can be described by a generic phenomenological mathematical model, The Epileptor. In this model, seizure-like events (SLEs) are driven by a slow variable and occur via saddle node (SN) and homoclinic bifurcations at seizure onset and offset, respectively. Here we investigated SLEs at the single cell level using a biophysically relevant neuron model including a slow/fast system of four equations. The two equations for the… 
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The mean field model is analytically exact for non-autonomous ion concentration variables and provides a mean field approximation in the thermodynamic limit, for locally homogeneous mesoscopic networks of biophysical neurons driven by an ion exchange mechanism.


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A network model of spiking neurons is developed and it is demonstrated that spike waves, including interictal spikes, are generated primarily by inhibitory neurons, whereas fast discharges during the wave part are due to excitatory neurons.
Local Dynamics of Ion-Based Neuron Models for Cortical Spreading Depression, Stroke and Seizures
The bifurcation analysis shows that a closed neuron system can only recover from FES if the rate of the ion pumps is extremely enhanced, and proves the coexistence of a physiological resting state and FES in a large number of reduced ion–based model variants.
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The results demonstrate that unified frameworks for neuronal dynamics are feasible, can be achieved using existing biological structures and universal physical conservation principles, and may be of substantial importance in enabling the understanding of brain activity and in the control of pathological states.
Electrogenic properties of the Na⁺/K⁺ ATPase control transitions between normal and pathological brain states.
The study demonstrates the profound role of the current mediated by Na(+)/K(+) ATPase on the stability of neuronal dynamics that was previously unknown.
Oxygen and seizure dynamics: II. Computational modeling.
A biophysical model is developed that accounts for metabolic energy consumption during and following seizure events and reproduces the interplay between excitatory and inhibitory neurons seen in experiments, accounting for the different oxygen levels observed during seizures inexcitatory vs. inhibitory cell layers.
The influence of depolarization block on seizure-like activity in networks of excitatory and inhibitory neurons
It is demonstrated that extracellular potassium concentration affects the depolarization block threshold; the consequent changes in bifurcation structure enable the network to produce the tonic to clonic phase transition observed in biological epileptic networks.
Simulated seizures and spreading depression in a neuron model incorporating interstitial space and ion concentrations.
It is concluded that epileptiform neuronal behavior and SD-like depolarization can be generated by the feedback of ion currents that change ion concentrations, which, in turn, influence ion currents and membrane potentials.