Source: Neuron Image; Public Domain: http://en.wikipedia.org/wiki/File:Chemical_synapse_schema_cropped.jpg
The state in which a neuron is not firing or sending a neural impulse and when there is a negative electrical charge inside the neuron.
The level or point at which a neuron fires, or a neural impulse is triggered.
The state in which a neuron reaches its Threshold of Excitation and fires, or sends an electrical impulse down the axon.
Small tunnels along a neuron that to pump ions from one side of the cellular membrane to the other, which creates an electrical charge.