Glossary
Neuromodulation
What is Neuromodulation?
Neuromodulation describes changes in neuronal or circuit function produced by modulatory signals. These signals can alter intrinsic firing properties and the strength of synaptic transmission.
How it works
Chemical neuromodulators include dopamine, serotonin, norepinephrine and acetylcholine. Neuromodulators may be released locally, through projection neurons, or through circulating signals. Their effects depend on receptors and circuit state. Assigning each chemical one function, such as mood or motivation, misses this diversity.
Applied example
Marder’s review describes the pyloric circuit in the crustacean stomatogastric nervous system, which generates rhythmic motor activity. In one experiment illustrated in Figure 5, stimulating the lateral pyloric neuron produces an inhibitory response in the pyloric dilator neuron. Applying dopamine, serotonin or octopamine changes that synaptic response. The same connected pair can therefore interact differently under different chemical conditions, helping explain how a circuit changes its output without requiring a new anatomical wiring diagram.
Why it matters
Neuromodulation helps explain why the same anatomical circuit can produce different activity patterns. The term is also used clinically for interventions that alter nervous-system activity, a broader usage than the chemical process described here.
Research: Marder (2012) explains how modulation can change a circuit’s functional output.