Synaptic potential
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Synaptic potential is a phenomenon in neurobiology, regarding the electric potential in a synapse. It normally considers the postsynaptic potential, but can also regard the presynaptic potential, e.g. by homotropic signals.
[edit] Examples
For instance, synpatic transmission normally generates either a excitatory postsynaptic potential (EPSP) or an inhibitory postsynaptic potential (IPSP). However, neurotransmitters can also affect the membrane potential of the same neuron that they originated from, and thus cause an excitatory presynaptic potential or an inhibitory presynaptic potential. Unlike action potentials, which are all or none, synaptic potentials are graded and can be summed if the potentials are very close together. That is because there is no refractory period, as there is in an action potential.