Depending on whether they are elicited by receptors that produce fast changes or receptors that produce slow changes

Depending on whether they are elicited by excitatory or inhibitory synapses

Depending on whether they are elicited by receptors that are ion channels or receptors linked to G proteins

Depending on the direction of change in the post-synaptic potential

Depending on the mechanism producing the change in the post-synaptic potential