[MUSIC] So we just looked at the hypothalamus as essentially a pump and that pump can go awry. If the pumping cells start to multiply there's too much hormone that's pumped out and that creates problems. But what we're going to look at now is a slightly more nuanced issue. So and it shows I think the power of the hypothalamus and the power of the, of the central nervous system in general. Okay, so, what this hypothalamus is able to do by recruiting not only the autonomic nervous system, but also the skeletal motor system and, by recruiting telencephalic mood and motivation circuits, is to produce behavioral packages that make sense. And this is one of my cats in one of these be, behavioral packages. She is in a fight or imagine she is in a fight. She's got her hair raised, she's got, popped up her tail, she's extremely alert. Her eyes are, her pupils are dilated and she is ready to go. So that kind of behavioral package is very useful. We're not going to look at this one in detail, what we're going to look at is the behavioral package that goes with having a baby. So. When a, a baby comes into the world, in these modern days, there are, there are many challenges. First of all, the body, the, the mother's body changes at birth and through the months following birth. Is a very, it's, it's essentially a hormonal storm that rivals adolescence. There's a sleep, there's a sleep deprivation that occurs. There is a baby who is entirely dependent on the mother, 24 hours a day, seven days a week. And prior to modern days we have evolved in a situation where there were no, there was no help, there was no nannies, there was no pumping your milk and giving it to the baby at a different time. So we evolved under situation where the stress on the mother was extreme. and, there are two hormones that are, involved in postpartum behavior and mood. And one is oxytocin. And oxytocin is, involved in, giving birth, it, it actually has peripheral effects on, on the uterus. And promotes partition or birth, and it stays elevated for many months after, after giving birth. And the other one is a hormone called prolactin, and prolactin is stimulated by nipple stimulation. In fact it's stimulated when a baby suckles. So that that elicits a release prolactin from the hypothalamus via the pituitary. And in turn the prolactin then acts on the mammary ducts to release, to let the milk down. So that's great, but would it work to let the milk down if you felt really uptight, if you were very agitated, if you were scared, if you were. Freezing cold. No, you have to be in a calm place. And this, this mother, this is a picture taken in Spain, I think in Valencia. And she's found herself a nice quiet place in the middle of the city where she can nurse her baby. And in fact, the reason that this package works is because oxytocin and prolactin have besides their peripheral facts on the uterus and on, on the memory glands, they have effects on our mood. They are essentially the, the duo act as essentially a chill pill. They really ease a mother's, abilities, stress reactivity. So, things that might stress her out in a different situation now that in, in this postpartum period, they don't stress her out as much. They produce a calm, quiet mood. They also enhance bonding with the baby. These are, these, these hormones are active centrally, and I would even argue that they're, they're central actions are as critical, to, motherhood and parenthood as as are their peripheral actions. Now the most common thing that goes wrong in the postpartum period is that there is a postpartum mood disorder. And the most common one is postpartum anxiety. Although postpartum depression and postpartum psychosis are, are have, grab more attention in the headlines. Regardless, all of these postpartum mood disorders are thought to be, at least in part, due to some, some problem with the release of oxytocin and prolactin. So the, the oxytocin, can be replaced. And in fact, now there's been, there's been this amazing, new treatment, which is that we can now give women internasally delivered oxytocin. And in a large number of women, this really helps with postpartum mood disorders. So this is a really exciting discovery, it's one that came out of basic science work in rodents, we didn't learn about this initially from women, but we've been able to apply it to women. And it's really one of the most exciting new treatments to develop out of neurobiology. So that's what we're going to look at for the hypothalamus. And now we're going to look at these, in the next module we'll look at these other homeostatic functions. And we'll start with one of the easiest and, and most illustrative examples and that's thermoregulation. [MUSIC]
