A neuron, or nerve cell, is the basic unit of the brain and nervous system. Neurons are specialised to transmit information as electrical and chemical signals. For communication to occur between neurons, an electrochemical change known as an action potential must first be generated in the neuron.

An unstimulated neuron is a neuron that is not currently transmitting an action potential. This means that the neuron is in its resting state and is not firing. In this state, the neuron is polarised, meaning that the inside of the cell is negative compared to the outside. This difference in electrical charge is maintained by the sodium-potassium pump, which is a protein in the neuron's cell membrane that actively transports sodium and potassium ions across the membrane.

When a neuron is stimulated, the membrane potential changes, causing the neuron to fire an action potential if the stimulus is strong enough to reach the neuron's threshold potential. The action potential is a wave of depolarisation that travels along the neuron's axon, transmitting the signal to the neuron's target cells.

After the action potential has been generated, the neuron returns to its resting state and is once again unstimulated.