A standard leaky-integrate-and-fire neuron model is implemented where the membrane potential of a neuron is given by
where is the membrane time constant, is the membrane resistance, is a non-specific background current and is a Gaussion random variable with zero mean and a given variance noise.
This neuron efficiently implements 4 types of synaptic channels (NMDA, AMPA, GABA A, GABA B). plus the standard synaptic cannel. The synaptic current is the sum of the 5 currents from the syn. channels. For NMDA, AMPA, GABA A, and GABA B, the synaptic conductance is increased by each synapse (see synapses) and then decays with the respective time constants . The current is given by .
At time ist set to . If exceeds the threshold voltage it is reset to and hold there for the length of the absolute refractory period.
The exponential Euler method is used for numerical integration.