Figure 4. Field recordings of evoked excitatory postsynaptic potentials (EPSPs) showing paired pulse facilitation. Traces shown are for control, 5.0 micro Meter riluzole, and an overlay for comparison. Two time-versus-amplitude graphs of EPSP amplitudes show a marked reduction in both the first and second pulse responses after a 20-min application of riluzole (heavy line). Points represent the mean plus/minus SEM for five determinations from separate slices. Note the decrease in paired pulse facilitation that accompanied EPSP depression.