Serotonin acts as a ligand that binds to serotonin receptors, altering neuron activity, promoting growth factor release, changing gene expression, and influencing cell proliferation and robustness.

“The receptors, in this case, serotonin receptors, have the opportunity to do all sorts of different things. They can change the activity of neurons making them more active or less active. They can cause growth factors to be released making sure that those neurons reinforce or even build up stronger connections so that they're more likely to be active in the future. Serotonin binding to particular receptors can even change the gene expression in particular cells making those cells proliferate.”