Inter-spike interval: 40.0 ms. Summation only matters when this is short compared to the decay below.
Postsynaptic integration
20 ms
5 ms (fast)60 ms (slow)
Stands in for the postsynaptic membrane time constant. Longer τ lets each EPSP linger, so more of it is still there when the next one arrives.
If summed depolarization reaches −55 mV, a somatic action potential is triggered. Only shown in EPSP mode — field potentials here don't spike.
Presynaptic facilitation (residual Ca²⁺)
35%
How much leftover Ca²⁺ from prior pulses boosts release on the next one. Zero = every EPSP is the same size; only passive summation is left.
70 ms
20 ms200 ms
Presynaptic depression (vesicle depletion)
30%
Fraction of the currently-available vesicle pool released per spike (scaled by facilitation, so a more facilitated spike also depletes more). Zero = an inexhaustible pool, facilitation only.
400 ms
50 ms (fast)1500 ms (slow)
How quickly depleted resources refill between spikes. Facilitation and depression now compete for each EPSP's amplitude.