The suprachiasmatic nucleus influences the autonomic nervous system, hormonal systems, and higher brain centers that organize rational behavior.

“Now what happens then is not that well understood, but it's clear that this is a neural center that has the same ability to communicate with other parts of your brain as any other neural center. And clearly, there are circuits that involve connections between neurons that are conventional. But in addition, it's quite clear that there are also sort of humeral effects that things are being oozing out of the cells in the center and maybe into the circulation or just diffusing through the brain to some extent that can also affect neurons elsewhere.”