Experiment. Ictal and interictal discharges in voltage-clamp (<i>V</i>_<i>hold</i> = −27 mV) in isolated entorhinal cortex slice.

<p>A: Transitions between 3 modes of synchronized synaptic activity in the isolated cortex: IID1, seizure-like events (SLEs) and IID1. B: Expanded traces from A with the representative current patterns.</p

Model. The activity of interneurons during IID1s.

<p>A: the firing rate and the mean membrane potential. B: the synaptic conductances. The simulation corresponds to that in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0185752#pone.0185752.g005" target="_blank">Fig 5</a>. <i>V</i>_<i>GABA</i> = −50 mV.</p

Experiment. Interictal discharges in combined entorhinal cortex-hippocampal slices.

<p>A: IID1 (left) and IID2 (right) recorded in voltage-clamp at (<i>V</i>_<i>hold</i> = −27 mV). B: synaptic conductances underlying the discharges, estimated with the method from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0185752#pone.0185752.ref014" target="_blank">14</a>].</p

Experiment and model. Mean ratios of maximum synaptic conductances during IID1 and IID2. The statistics is done for averaged IID1 from 5 cells and averaged IID2 from 10 cells in experiment, and 107 IID1 and 32 IID2 in simulation.

<p>Experiment and model. Mean ratios of maximum synaptic conductances during IID1 and IID2. The statistics is done for averaged IID1 from 5 cells and averaged IID2 from 10 cells in experiment, and 107 IID1 and 32 IID2 in simulation.</p

Model. IID2s.

<p>A: Local field potential (LFP) at the interval of 32s after the beginning of spontaneous current injection (20 pA amplitude, 4 ms correlation time). B-E: characteristics of the discharges on 2.4 s interval: B: LFP. C: the membrane current at <i>V</i>_<i>hold</i> = −27mV. D: the firing rate and the mean membrane potential. E: the synaptic conductances. <i>V</i>_<i>GABA</i> = −45mV.</p

Experiment. Evoked IPSCs.

<p>IPSCs recorded at the holding voltage 0 mV in the control solution (top) and pro-epileptic solution (bottom) in response to stimulation by a train of 25 pulses of extracellular stimulation at 20 Hz.</p

Schematic of connections between populations of excitatory neurons (E) and interneurons (I) involved in the generation of IID1 and IID2.

<p>The excitatory neurons have two, somatic and dendritic compartments, which receive GABAergic and glutamatergic inputs. The single-compartment interneurons receive glutamatergic input, noisy excitatory input-current and recurrent GABAergic drive. A, During IID1s the excitatory neurons do not fire. Interneurons receive recurrent excitation through GABAergic synapses. This case is modeled by setting <i>V</i>_<i>GABA</i> = −50 mV. B, During IID2s the excitatory neurons are triggered by spontaneous activity of interneurons by means of depolarizing GABAergic synapses. This case is modeled by setting <i>V</i>_<i>GABA</i> = −45 mV. Note that the schematic in A includes only the connections that are activated during IID1, whereas during IID2 all those connections that are included in the model are activated, as plotted in B.</p

Model. IID1s. Short-term synaptic depression.

<p>A: field potential. B: short-term synaptic depression variables and . C: the membrane current at <i>V</i>_<i>h</i> = −27mV in a representative excitatory neuron. The simulation corresponds to that in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0185752#pone.0185752.g005" target="_blank">Fig 5</a>.</p

Model. IID1s.

<p>A: Local field potential (LFP) at the interval of 32s after the beginning of spontaneous current injection (20 pA amplitude, 4 ms correlation time). B-E: characteristics of the discharges on 2.4 s interval: B: LFP. C: the membrane current at <i>V</i>_<i>hold</i> = −27mV. D: the firing rate and the mean membrane potential. E: the synaptic conductances. <i>V</i>_<i>GABA</i> = −50 mV.</p

Model. Field potential and membrane voltage during IID2s.

<p>A: field potential. B: membrane voltage in a representative excitatory neuron.</p