Figure 3. A graphical illustration of the chronotron problem for a neuron with 3 synapses.
(A) The dynamics of the membrane potential 
. The numbered arrows indicate the timings when the membrane potential reaches the firing threshold and spikes are fired. (B) The dynamics of the three components of 
. (C) The trajectory of 
. Spikes are generated when the trajectory reaches the spike-generating hyperplane, which is here the black plane. The numbered arrows indicate the generation of spikes at the timings when the spike-generating hyperplane is reached. The neuron has 
.