Synaptic potential

The type of potential produced depends on both the postsynaptic receptor, more specifically the changes in conductance of ion channels in the post synaptic membrane, and the nature of the released neurotransmitter.

The neuron will account for all the many incoming excitatory and inhibitory signals via summative neural integration, and if the result is an increase of 20 mV or more, an action potential will occur.

Both EPSP and IPSPs generation is contingent upon the release of neurotransmitters from a terminal button of the presynaptic neuron.

As an action potential travels through the presynaptic neuron, the membrane depolarization causes voltage-gated calcium channels to open.

The released neurotransmitter then binds to its receptor on the postsynaptic neuron causing an excitatory or inhibitory response.

Whether the effects are combined in space or in time, they are both additive properties that require many stimuli acting together to reach the threshold.

The quantity of neurotransmitters released can play a large role in the future strength of that synapse's potential.

Some of these mechanisms rely on changes in both the presynaptic and postsynaptic neurons, resulting in a prolonged modification of the synaptic potential.

[8] In recent years, there has been an abundance of research on how to prolong the effects of a synaptic potential, and more importantly, how to enhance or reduce its amplitude.

The enhancement of synaptic potential would mean that fewer would be needed to have the same or larger effect, which could have far-reaching medical uses.

Graph shows how the IPSP hyperpolarizes the membrane and EPSP depolarizes the membrane. If the two are summed together, the action potential threshold is still not reached.
Graph showing the effects of EPSPs and IPSPs on membrane potential.