True about summation is?

Subthreshold stimuli are used.SummationA subthreshold stimulus does not produce a response, but when more than one subthreshold stimuli are applied in response is produced.The application of two subthreshold stimuli may be sufficiently quickly, one by another (temporal summation) or two subthreshold stimuli together at different places(Spatial summation).The summation is due summation of EpsP in synapses (at post-synaptic neuron).