Summation of postsynaptic potentials.
Subthreshold, no summation. A single EPSP may be too small to trigger an action potential in a postsynaptic neuron.		Temporal summation occurs when two EPSPs are produced in rapid succession.		Spatial summation occurs when different synapses produce EPSPs on the same postsynaptic neuron simultaneously.		Spatial summation of EPSP and IPSP. An IPSP can counter the effect of an EPSP.