CbStOuNeuron
Subsections
CbStOuNeuron
The membrane voltage V _{m} is governed by
with the following meanings of symbols
C _{m} membrane capacity (Farad)
E _{m} reversal potential of the leak current (Volts)
R _{m} membrane resistance (Ohm)
N _{c} total number of channels (active + synaptic)
g _{c} (t ) current conductance of channel c (Siemens)
E _{rev} ^{c} reversal potential of channel c (Volts)
N _{s} total number of current supplying synapses
I _{s} (t ) current supplied by synapse s (Ampere)
G _{s} total number of coductance based synapses
g _{s} (t ) coductance supplied by synapse s (Siemens)
E _{rev} ^{(s)} reversal potential of synapse s (Volts)
g _{noise} ^{exz} (t ) excitatory coductance given Ornstein Uhlenbeck process noise
E _{noise} ^{exc} reversal potential for excitatory Ornstein Uhlenbeck process noise
g _{noise} ^{inh} (t ) inhibitory coductance given Ornstein Uhlenbeck process noise
E _{noise} ^{inh} reversal potential for inhibitory Ornstein Uhlenbeck process noise
I _{inject} injected current (Ampere)
At time t =0 V _{m} ist set to V _{init} .
The value of E _{m} is calculated to compensate for ionic currents such that V _{m} actually has a resting value of
.
If the membrane voltage V _{m} exceeds the threshold V _{tresh} the CbNeuronSt sends a spike to all its outgoing synapses and the membrane voltage follows a predefined spike templage during the absolute refractory period of length T _{refract} if doReset = 1 .
If the flag doReset=0 the spike template is not applied and the above equation is also applied during the absolute refractory period but the event of threshold crossing is transmitted as a spike to outgoing synapses. This is usfull if one includes channels which produce a real action potential (see HH_K_Channel and HH_Na_Channel ) but one still just wants to communicate the spikes as events in time.
The exponential Euler method is used for numerical integration.
ge (S ) :
exc and inh conductances (noise)
gi (S ) :
exc and inh conductances (noise)
ge0 (S ) :
exc and inh mean conductances (noise)
gi0 (S ) :
exc and inh mean conductances (noise)
tau_e (S ) :
time constants and std for exc and inh conductances (noise)
tau_i (S ) :
time constants and std for exc and inh conductances (noise)
sig_e (S ) :
time constants and std for exc and inh conductances (noise)
sig_i (S ) :
time constants and std for exc and inh conductances (noise)
Ee (V ) :
Reversal potential for exc and inh currents (noise)
Ei (V ) :
Reversal potential for exc and inh currents (noise)
STempHeight (Volt ) :
Height
Vthresh (V ) :
If V _{m} exceeds V _{thresh} a spike is emmited.
Vreset (V ) :
The voltage to reset V _{m} to after a spike.
doReset (flag ) :
Flag which determines wheter V _{m} should be reseted after a spike
Trefract (sec ) :
Length of the absolute refractory period.
nummethod (flag ) :
Numerical method for the solution of the differential equation: Exp. Euler = 0, Crank-Nicolson = 1
type :
Type (e.g. inhibitory or excitatory) of the neuron
Cm (F ) :
The membrane capacity C _{m}
Rm (Ohm ) :
The membrane resistance R _{m}
Vresting (V ) :
The resting membrane voltage.
Vinit (V ) :
Initial condition forV _{m} at time t =0 .
VmScale (V ) :
Defines the difference between Vresting and the Vthresh for the calculation of the iongate tables and the ionbuffer Erev.
Inoise (W ^{2} ) :
Variance of the noise to be added each integration time constant.
Iinject (A ) :
Constant current to be injected into the CB neuron.
Em (V ) :
The reversal potential of the leakage channel
Vm (V ) :
The membrane voltage
OuInoise :
noise input current
OuGnoise :
noise input conductance
Isyn :
synaptic input current
Gsyn :
synaptic input conductance
nIncoming :
Number of incoming synapses
nOutgoing :
Number of outgoing synapses
nBuffers :
Number of ion buffers
nChannels :
Number of channels