Fig. 1.

Fit of EJPs by a sum of single-spike responsesK₁. Open circles show recorded EJPs evoked by a pair of spikes. The solid lineis a prediction using a linear sum of two single-spike responsesK₁. K₁ was chosen to fit single isolated spikes, and it fits the first EJP accurately. Although temporal summation is seen, the prediction based on a sum of single-spike responses fails to account for the facilitation displayed by the data. Data are from a gm8 muscle with a baseline membrane potential of −59 mV.