Izhikevich Neuron

The Izhikevich model neuron was developed as an efficient, powerful alternative to the integrate and fire model. The model uses two variables, a variable representing voltage potential and another representing membrane recovery (activation of potassium currents and inactivation of sodium currents).

This is a spiking neuron, so when the voltage passes a threshold value a spiking event occurs, the GUI neuron turns yellow, and the voltage and recovery variable are reset.

Since a is a parameter of the model, we use v to represent activation (voltage potential). u represents the recovery variable. Voltage is computed by integrating the following two differential equations using Euler's method:

 

W is weighted inputs; a and b are abstract parameters of the model.

When the voltage exceeds a threshold value, which is preset at 30, both v and u are reset, as follows:

Thus there are four parameters for this system. According to Izhikivech, "The model can exhibit firing patterns of all known types of cortical neurons with [a suitable] choice of parameters"

 

See Eugene Izhikevich (2004), "Which Model to Use For Cortical Spiking Neurons," IEEE Transactions on Neural Networks.

 

Time step

See time-step.

A

Parameter for recovery variable.

B

Parameter for recovery variable.

C

The value for v which occurs after a spike.

D

A constant value added to u after spikes.

Add Noise

If this is set to true, random values are added to the activation via a noise generator.