| Symbol . | Value . | Description . |
|---|---|---|
| Δt | 0.1 ms, 0.01 ms | Duration of one time step for network and single-neuron simulations, respectively |
| tmax | 20 s | Total duration of the simulations |
| tpulse | 4 ms | Duration of one light pulse |
| λmax | 470 nm | Wavelength of light, absorption maximum of ChR2/H134R (Williams et al., 2013) |
| τChR2 | 1.3 ms | Activation time constant for channels (Nikolic et al., 2009) |
| σret | 12 ⋅ 10−20 m2 | ChR2 retinal absorption cross-section (Williams et al., 2013) |
| gChR2 | 100 fS | Single channel conductance (Lin, 2011) |
| wloss | 1.3 | Loss factor accounting for the environment of a channel (Nikolic et al., 2009) |
| Γd,0 | 126.74 1/s | Desensitization rate at a potential of −70 mV (Tchumatchenko et al., 2013) |
| Γr | 8.38 1/s | Recovery rate (Tchumatchenko et al., 2013) |
| ϵ | 0.5 | Quantum efficiency for channel opening (Nikolic et al., 2009) |
| τm | 10 ms | Membrane time constant |
| τref | 3 ms | Duration of the refractory period |
| gm | 0.1 μS | Absolute membrane conductance, excluding ChR2 conductances |
| Vrev | −65 mV | Reversal (equilibrium) potential |
| Vreset | −70 mV | Reset potential |
| Vth | −55 mV | Threshold potential to be crossed for spiking |
| NChR2 | 60 000, 300 000 | Number of ChR2 channels within one neuron |
| σwn | 0.01 nA | Standard deviation for Gaussian noise in external fluctuations |
| I0 | 0.914576 nA | Mean of the external fluctuations (given value is for a single neuron) |
| σlight | 8 grid units | Standard deviation of the spatial Gaussian distribution of light |
| NE | 3 600 = 60 × 60 | Number of neurons in the excitatory population, aligned in a square |
| NI | 900 | Number of neurons in the inhibitory population |
| pc | 0.005–0.015 | Connectivity (probability of connection between two neurons) (Braitenberg & Schüz, 1998; Le Duigou et al., 2014) |
| τsyn | 5 ms | Synaptic time constant, also for external fluctuations |
| Symbol . | Value . | Description . |
|---|---|---|
| Δt | 0.1 ms, 0.01 ms | Duration of one time step for network and single-neuron simulations, respectively |
| tmax | 20 s | Total duration of the simulations |
| tpulse | 4 ms | Duration of one light pulse |
| λmax | 470 nm | Wavelength of light, absorption maximum of ChR2/H134R (Williams et al., 2013) |
| τChR2 | 1.3 ms | Activation time constant for channels (Nikolic et al., 2009) |
| σret | 12 ⋅ 10−20 m2 | ChR2 retinal absorption cross-section (Williams et al., 2013) |
| gChR2 | 100 fS | Single channel conductance (Lin, 2011) |
| wloss | 1.3 | Loss factor accounting for the environment of a channel (Nikolic et al., 2009) |
| Γd,0 | 126.74 1/s | Desensitization rate at a potential of −70 mV (Tchumatchenko et al., 2013) |
| Γr | 8.38 1/s | Recovery rate (Tchumatchenko et al., 2013) |
| ϵ | 0.5 | Quantum efficiency for channel opening (Nikolic et al., 2009) |
| τm | 10 ms | Membrane time constant |
| τref | 3 ms | Duration of the refractory period |
| gm | 0.1 μS | Absolute membrane conductance, excluding ChR2 conductances |
| Vrev | −65 mV | Reversal (equilibrium) potential |
| Vreset | −70 mV | Reset potential |
| Vth | −55 mV | Threshold potential to be crossed for spiking |
| NChR2 | 60 000, 300 000 | Number of ChR2 channels within one neuron |
| σwn | 0.01 nA | Standard deviation for Gaussian noise in external fluctuations |
| I0 | 0.914576 nA | Mean of the external fluctuations (given value is for a single neuron) |
| σlight | 8 grid units | Standard deviation of the spatial Gaussian distribution of light |
| NE | 3 600 = 60 × 60 | Number of neurons in the excitatory population, aligned in a square |
| NI | 900 | Number of neurons in the inhibitory population |
| pc | 0.005–0.015 | Connectivity (probability of connection between two neurons) (Braitenberg & Schüz, 1998; Le Duigou et al., 2014) |
| τsyn | 5 ms | Synaptic time constant, also for external fluctuations |
Note. Unless stated otherwise, the values were used as stated in this table.