 All right, norepinephrine is a substance, this is what it looks like. Norepinephrine is essentially adrenaline, and so it tends to be excitatory. However, apparently in the brain, it can actually inhibit responses. But norepinephrine, anything related to norepinephrine is going to be called adrenergic. And you have different flavors of adrenergic receptors. You can have alpha receptors and beta receptors. And we'll talk about these in more detail, but I'm telling you, I'm giving you my different flavors now because you remember that one of the ways that we can fine-tune the information or vary the responses to a single molecule by having different receptors in different places. Yeah, we've already talked about that. This is an example, norepinephrine, I have to write it down so I don't forget who I'm talking about, norepinephrine. Norepinephrine is an example of a neural hormone because there's a very specific place where we literally dump norepinephrine into the blood, and we're going to talk about that more in detail. It's part of the fight-or-flight response, it's part of the sympathetic nervous response, and like I said, usually it gets everything ramped up, but sometimes it inhibits things in the brain. We'll talk about it more in detail more later. Let's talk about serotonin. Oops, there it is on the website. Now, let's talk about serotonin.