iaf_psc_exp_g – Leaky integrate-and-fire neuron model with exponential PSCs and same parameters within a population
Description
iaf_psc_exp_g is an implementation of a leaky integrate-and-fire model with exponential shaped postsynaptic currents (PSCs) according to equations 1, 2, 4 and 5 of [1] and equation 3 of [2]. Thus, postsynaptic currents have an infinitely short rise time.
This model enables only the change of parameters for the whole population of neurons created within a single Create command. For having the possibility of changing the parameters for single neurons belonging to a neuron population please chose the iaf_psc_exp neuron model.
The threshold crossing is followed by an absolute refractory period (t_ref) during which the membrane potential is clamped to the resting potential and spiking is prohibited.
The linear subthreshold dynamics is integrated by the Exact Integration scheme [3]. The neuron dynamics are solved on the time grid given by the computational step size. Incoming as well as emitted spikes are forced into that grid.
An additional state variable and the corresponding differential equation represent a piecewise constant external current.
For conversion between postsynaptic potentials (PSPs) and PSCs,
please refer to the postsynaptic_potential_to_current
function in
the helpers.py
script of the Cortical Microcircuit model of [4].
Parameters
The following parameters can be set in the status dictionary.
V_m_rel |
mV |
Membrane potential in mV (relative to resting potential) |
I_syn_ex |
pA |
Excitatory synaptic current |
I_syn_in |
pA |
Inhibitory synaptic current |
tau_m |
ms |
Membrane time constant |
C_m |
pF |
Capacity of the membrane |
E_L |
mV |
Resting membrane potential |
I_e |
pA |
Constant input current |
Theta_rel |
mV |
Spike threshold in mV (relative to resting potential) |
V_reset_rel |
mV |
Reset membrane potential after a spike |
tau_ex |
ms |
Exponential decay time constant of excitatory synaptic current kernel |
tau_in |
ms |
Exponential decay time constant of inhibitory synaptic current kernel |
t_ref |
ms |
Duration of refractory period (V_m = V_reset) |
den_delay |
ms |
Dendritic delay |