excitatory post-synaptic potentials (EPSPs) and summation

• • when an action potential moves along an axon, it will eventually result in the release of a neurotransmitter (acetylcholine). the release of this transmitter substance will cause a depolarisation on the post synaptic membrane. This is known as a excitatory post-synaptic potential (EPSP)
• • in reality, the release of a small amount of neurotransmitters isn't enough to cause an action potential in the post synaptic membrane
  • in fact, several ESPs (generator potentials) will be necessary to combine together. Their combined effect is needed to reach the threshold and cause an action potential. This combined effect is called summation