Neurons are able to generate action potentials under stimulation and response in different manner under the actions of varied external stimulations. The different abilities and characteristics of a neuron represent its excitability. Traditional definition of neuronal excitability is based on the neuron's ability to produce action potentials under certain stimulation. Excitability is the intrinsic property of the neuron. It can be defined by the threshold potential of the neuron or by threshold stimul...