a group of biologically active substances synthesized in neurons and having a modulating effect on the transmission of signals between neurons. The main representatives of neuromodulators are acetylcholine, serotonin, dopamine, and norepinephrine. They affect the general condition of nervous tissue, change the excitability of neurons, and regulate a wide range of processes, such as attention, mood, memory, and motor skills. The effectiveness of neuromodulatory systems significantly determines the general level of performance and health of a person.