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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 multicompartment models in
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
C_m.s d/dt V_m.s = ... - g_sp ( V_m.s - V_m.p )
C_m.p d/dt V_m.p = ... - g_sp ( V_m.p - V_m.s ) - g_pd ( V_m.p - V_m.d )
C_m.d d/dt V_m.d = ... - g_pd ( V_m.d - V_m.p )
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 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 normalised 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!
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* double - Membrane potential in mV
E_L* double - Leak reversal potential in mV.
C_m* double - Capacity of the membrane in pF
E_ex* double - Excitatory reversal potential in mV.
E_in* double - Inhibitory reversal potential in mV.
g_L* double - Leak conductance in nS;
tau_syn_ex* double - Rise time of the excitatory synaptic alpha function in ms.
tau_syn_in* double - Rise time of the inhibitory synaptic alpha function in ms.
I_e* double - Constant input current in pA.
g_sp double - Conductance connecting soma and proximal dendrite in nS.
g_pd double - Conductance connecting proximal and distal dendrite in nS.
t_ref double - Duration of refractory period in ms.
V_th double - Spike threshold in mV.
V_reset double - Reset potential of the membrane in mV.
This is a prototype for illustration which has undergone only limited testing.
Details of the implementation and user-interface will likely change.
USE AT YOUR OWN PERIL!