In
neuroscience, an
excitatory postsynaptic potential (
EPSP) is a
postsynaptic potential that makes the neuron more likely to fire an
action potential. This temporary depolarization of postsynaptic
membrane potential, caused by the flow of positively charged
ions into the postsynaptic cell, is a result of opening
ligand-gated ion channels. These are the opposite of
inhibitory postsynaptic potentials (IPSPs), which usually result from the flow of
negative ions into the cell or positive ions
out of the cell. EPSPs can also result from a decrease in outgoing positive charges, while IPSPs are sometimes caused by an increase in positive charge outflow. The flow of ions that causes an EPSP is an
excitatory postsynaptic current (EPSC).