Figure 4.

A, Leaky integrate-and-fire neuron. The membrane potential of a leaky neuron is shown as plotted by the voltmeter item. As can be seen, the membrane potential increases until it reaches its threshold value and is immediately reset to the initial potential. The spike itself is overlayed as a vertical line for illustrative purposes and is not explicitly included in the dynamics of the membrane potential. B, Adaptive leaky integrate-and-fire neuron. The membrane potential of an adaptive neuron as plotted by the voltmeter item. This neuron receives input from the same DC current source. The interval between each spike of the adaptive neuron increases due to the an additional hyperpolarizing current, which grows for each spike and decays between the spikes.