iaf_cond_beta

iaf_cond_beta - Simple conductance based leaky integrate-and-fire neuron model

Description

iaf_cond_beta is an implementation of a spiking neuron using IAF dynamics with conductance-based synapses. Incoming spike events induce a post-synaptic change of conductance modelled by a beta function. The beta function is normalised such that an event of weight 1.0 results in a peak current of 1 nS at \(t = \tau_{rise\_[ex|in]}\).

References

See also

iaf_cond_exp, iaf_cond_alpha

Parameters

Name

Physical unit

Default value

Description

C_m

pF

250pF

Capacitance of the membrane

g_L

nS

16.6667nS

Leak conductance

E_L

mV

-70mV

Leak reversal potential (aka resting potential)

refr_T

ms

2ms

Duration of refractory period

V_th

mV

-55mV

Threshold potential

V_reset

mV

-60mV

Reset potential

E_ex

mV

0mV

Excitatory reversal potential

E_in

mV

-85mV

Inhibitory reversal potential

tau_syn_rise_I

ms

0.2ms

Synaptic time constant excitatory synapse

tau_syn_decay_I

ms

2ms

Synaptic time constant for inhibitory synapse

tau_syn_rise_E

ms

0.2ms

Synaptic time constant excitatory synapse

tau_syn_decay_E

ms

2ms

Synaptic time constant for inhibitory synapse

F_E

nS

0nS

Constant external input conductance (excitatory).

F_I

nS

0nS

Constant external input conductance (inhibitory).

I_e

pA

0pA

constant external input current

State variables

Name

Physical unit

Default value

Description

V_m

mV

E_L

Membrane potential

refr_t

ms

0ms

Refractory period timer

is_refractory

boolean

false

g_in

real

0

inputs from the inhibitory conductance

g_in$

real

g_I_const * (1 / tau_syn_rise_I - 1 / tau_syn_decay_I)

g_ex

real

0

inputs from the excitatory conductance

g_ex$

real

g_E_const * (1 / tau_syn_rise_E - 1 / tau_syn_decay_E)

Equations

\[\frac{ dV_{m} } { dt }= \frac 1 { C_{m} } \left( { (-I_{leak} - I_{syn,exc} - I_{syn,inh} + I_{e} + I_{stim}) } \right)\]

Source code

The model source code can be found in the NESTML models repository here: iaf_cond_beta.

Characterisation

Synaptic response

iaf_cond_beta_neuron

f-I curve

iaf_cond_beta_neuron