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iaf_cond_alpha_mc – Multi-compartment conductance-based leaky integrate-and-fire neuron model¶
Description¶
THIS MODEL IS A PROTOTYPE FOR ILLUSTRATION PURPOSES. IT IS NOT YET FULLY TESTED. USE AT YOUR OWN PERIL!
iaf_cond_alpha_mc is an implementation of a multi-compartment spiking neuron using IAF dynamics with conductance-based synapses. It serves mainly to illustrate the implementation of ref:multicompartment models <multicompartment-models> in NEST.
The model has three compartments: soma, proximal and distal dendrite, labeled as s, p, and d, respectively. Compartments are connected through passive conductances as follows
A spike is fired when the somatic membrane potential exceeds threshold, \(V_{m.s} >= V_{th}\). After a spike, somatic membrane potential is clamped to a reset potential, :math:` V_{m.s} == V_{reset}`, for the refractory period. Dendritic membrane potentials are not manipulated after a spike.
There is one excitatory and one inhibitory conductance-based synapse onto each compartment, with alpha-function time course. The alpha function is normalized such that an event of weight 1.0 results in a peak current of 1 nS at \(t = \tau_{syn}\). Each compartment can also receive current input from a current generator, and an external (rheobase) current can be set for each compartment.
Synapses, including those for injection external currents, are addressed through the receptor types given in the receptor_types entry of the state dictionary. Note that in contrast to the single-compartment iaf_cond_alpha model, all synaptic weights must be positive numbers!
Parameters¶
The following parameters can be set in the status dictionary. Parameters for each compartment are collected in a sub-dictionary; these sub-dictionaries are called “soma”, “proximal”, and “distal”, respectively. In the list below, these parameters are marked with an asterisk.
V_m* |
mV |
Membrane potential |
E_L* |
mV |
Leak reversal potential |
C_m* |
pF |
Capacity of the membrane |
E_ex* |
mV |
Excitatory reversal potential |
E_in* |
mV |
Inhibitory reversal potential |
g_L* |
nS |
Leak conductance |
tau_syn_ex* |
ms |
Rise time of the excitatory synaptic alpha function |
tau_syn_in* |
ms |
Rise time of the inhibitory synaptic alpha function |
I_e* |
pA |
Constant input current |
g_sp |
nS |
Conductance connecting soma and proximal dendrite |
g_pd |
nS |
Conductance connecting proximal and distal dendrite |
t_ref |
ms |
Duration of refractory period |
V_th |
mV |
Spike threshold in mV |
V_reset |
mV |
Reset potential of the membrane |
Sends¶
SpikeEvent
Receives¶
SpikeEvent, CurrentEvent, DataLoggingRequest
References¶
- 1
Meffin H, Burkitt AN, Grayden DB (2004). An analytical model for the large, fluctuating synaptic conductance state typical of neocortical neurons in vivo. Journal of Computational Neuroscience, 16:159-175. DOI: https://doi.org/10.1023/B:JCNS.0000014108.03012.81
- 2
Bernander O, Douglas RJ, Martin KAC, Koch C (1991). Synaptic background activity influences spatiotemporal integration in single pyramidal cells. Proceedings of the National Academy of Science USA, 88(24):11569-11573. DOI: https://doi.org/10.1073/pnas.88.24.11569