A neuromodulator is a substance other than a neurotransmitter, released by a neuron at a synapse and conveying information to adjacent or distant neurons, either enhancing or damping their activities. Neurotransmitters are chemicals that are used to relay, amplify and modulate electrical signals between two neurons: the presynaptic neuron and the postsynaptic neuron. ... Neurons (also spelled neurones or called nerve cells) are the primary cells of the nervous system. ... Synapses allow nerve cells to communicate with one another through axons and dendrites, converting electrical signals into chemical ones. ...

A neuromodulator is a relatively new concept in the field and it can also be considered as a neurotransmitter that is not reabsorbed by the pre-synaptic neuron or broken down into a metabolite. Such neuromodulator end up spending a significant amount of time in the CSF (cortico-spinal fluid) and influencing (or modulating) the overall activity level of the brain. For this reasons, some neurotransmitters are also considered as neuromodulators. Examples of neuromodulators in this category: serotonin and acetylcholine. Neurotransmitters are chemicals that are used to relay, amplify and modulate electrical signals between two neurons: the presynaptic neuron and the postsynaptic neuron. ... In the anatomy of animals, the brain, or encephalon, is the supervisory center of the nervous system. ... Neurotransmitters are chemicals that are used to relay, amplify and modulate electrical signals between a presynaptic and a postsynaptic neuron. ... Neuromodulators modulate regions or circuits of the brain. ... Serotonin (5-hydroxytryptamine, or 5-HT) is a monoamine neurotransmitter synthesised in serotonergic neurons in the central nervous system and enterochromaffin cells in the gastrointestinal tract. ... The chemical compound acetylcholine, often abbreviated as ACh, was the first neurotransmitter to be identified. ...