Figure 5.

Illustration of buffer sizes for different simulation schemes in case of fully synchronous or asynchronous spikes. (A) All incoming spikes arrive synchronously: In the time-driven scheme the synaptic weight is updated in every time step of the simulation, so that only the current value of V_m,post needs to be available (green). In the event-driven scheme every synapse processes V_m,post from the last spike to the current one. Therefore, the relevant time trace needs to be stored (red). In the compressed event-driven scheme this part of V_m,post is processed only once and used to update the weight of all the synapses. Since the weight change is a function of the last spike time which is the same for all the synapses, only one value needs to be updated (blue). In this situation the length L of the compressed history is i = 1, see Table 1. (B) All incoming spikes arrive in different time bins: For the time-driven and the event-driven scheme the scenario is similar to (A). For the compressed event-driven scheme the number of values that need to be updated equals the number of incoming synapses K so that i = K.