The basic unit of neuromodulation is the neuron.
Neurons can receive stimuli to produce excitation and conduct the excitation, which in turn enables regulation of other tissues. The transmission of excitation from one neuron to another occurs mainly through synapses. The substances that transmit information between synapses are called neurotransmitters. Excitation is transmitted in one direction between synapses, but in both directions within a single neuron.
Neuromodulation is a very important form of regulation in the human body. Neuromodulation is rapid and targeted, but the duration of action may not be very long lasting. The central nervous system responds to external stimuli by forming nerve impulses that are transmitted through nerve fibers and neurotransmitters to surrounding tissues and organs.