Preoptic area

The?preoptic area?is a region of the?hypothalamus.?MeSH?classifies it as part of the anterior hypothalamus.?TA?lists four?nuclei?in this region, (medial, median, lateral, and periventricular).

Contents

·?1Functions

·?2Nuclei

·?2.1Median preoptic nucleus

·?2.2Medial preoptic nucleus

·?2.2.1Parental behavior

·?2.2.2sexual behavior

·?2.3Ventrolateral preoptic nucleus

·?2.4Preoptic periventricular nucleus

·?3References

Functions[edit]

The preoptic area is responsible for?thermoregulation?and receives nervous stimulation from?thermoreceptors?in the skin,?mucous membranes, and hypothalamus itself.[1]

Nuclei[edit]

Median preoptic nucleus[edit]

The?median preoptic nucleus?is located along the midline in a position significantly dorsal to the other three preoptic nuclei, at least in the?crab-eating macaque?brain. It wraps around the top (dorsal), front, and bottom (ventral) surfaces of the?anterior commissure.

The median preoptic nucleus generates?thirst. ?Drinking decreases?noradrenaline?release in the median preoptic nucleus.[2]

Medial preoptic nucleus[edit]

Main article:?sexually dimorphic nucleus

The medial preoptic nucleus is bounded laterally by the lateral preoptic nucleus, and medially by the preoptic periventricular nucleus. It releases?gonadotropin-releasing hormone?(GnRH), controls copulation in males, and is larger in males than in females.

Parental behavior[edit]

The medial preoptic area (mPOA) has been implicated in parental care in both males and females. In rats,?oxytocin?and?vasopressin?are associated with maintaining maternal care through local release in the mPOA and the adjacent bed nucleus of the?stria terminalis?(BNST)

(oxytocin?and?vasopressin?的作用應該是起到抑制mPOA and?bed nucleus of the?stria terminalis作用，事實上oxytocin在PAG和杏仁核處的作用就是降低這些核團的敏感性（母性的無畏應該是來自于腦島對杏仁核central nucleus的興奮作用）。mPOA被oxytocin?and?vasopressin抑制，而且雌、雄分泌oxytocin?and?vasopressin的比例應該不同，因此所產(chǎn)生的Parental behavior也是有所不同。如果mPOA沒有被抑制，可能就不產(chǎn)生Parental behavior，相反去產(chǎn)生gonadotropin-releasing hormone?(GnRH)。).?

Oxytocin and vasopressin V1a receptor binding are increased in both the mPOA and the BNST in lactating rats when compared to controls.[3]The mPOA also has a high density of?estradiol?receptors that, when activated, can cause a male rat to show maternal-type behaviors

（似乎這意味著那些雄性激素生產(chǎn)少的種類就不會出現(xiàn)雄性show maternal-type behaviors，現(xiàn)實中的人類群體似乎也是這樣，那些看起來兇一些的male（controlled more by hormone）對自己的孩子是非常溫柔的，show maternal-type behaviors，也就是mPOA同時受到性激素與oxytocin?and?vasopressin的明顯影響，這要依賴于mPOA投射到哪些結(jié)構(gòu)。）.

[4]?Additionally, the mPOA is critical for the onset and expression of parental behavior, as evidenced by increases in the immediate early gene?c-fos, in experienced rat mothers or fathers when compared to controls. Also in fathers, studies have shown that when they receive ultrasonic or pheromone cues from their mates, their c-fos expression in the mPOA further increased, suggestive that rat paternal behavior is mediated through the mPOA but activated by direct interactions with a mate.[5]?Large lesions of the mPOA disrupt the onset of maternal behavior, nest-building, and pup retrieval, with the lateral projections being especially critical.[6]

sexual behavior[edit]

The mPOA is sexually dimorphic, that is, it differs in function between males and females. In females, studies have examined the influence of the mPOA on precopulatory and appetitive behaviors. Precopulatory behaviors involve several brain areas, including the mPOA as well as the medial?amygdala?(MA) and BNST. Studies using female Syrian hamsters have shown that the mPOA is important for sexual odor preference. While control females will investigate male odors more than female odors, those with bilateral lesions to the mPOA (MPOA-X) will show no difference in odor preference, but vaginal scent marking and lordosis remained unaffected.[7]?appetitive behaviors of female rats – including hops, darts, and solicitations – have been linked to?dopamine?(DA) transmission in the mPOA. Since?ascorbic acid?(Vitamin C) enhances DA transmission in mesolimbic and nigrostriatal pathways, it has been shown that infusions of ascorbic acid into the mPOA increases appetitive behaviors compared to controls.[8]

In male rats, the mPOA affects the consummatory phase of sexual behavior, and possibly motivation, with lesions causing a complete loss of copulatory behaviors.[9]?Conversely, electrical stimulation of this area triggers male copulatory behavior, as measured by decreases in the latency to ejaculate.[10]?Furthermore,?testosterone?implanted into the mPOA of castrated males completely restores mating, as long as?aromatase?is not inhibited.[11]

（講了這么多medial preoptic area的重要功能，可是詞條中除了說gonadotropin-releasing hormone是由這里分泌之外，居然連一句如何與其他核團連接的內(nèi)容都沒有記載，這難道是解剖學上很難觀察到的嗎？還好知道是溫度信息的輸入目的地，一些動物的繁殖與季節(jié)溫度的變化緊密相關(guān)，還有一次我看到我手中的螳螂在受凍后開始產(chǎn)生進食行為--啃咬我的手指，大體能知道m(xù)edial preoptic area與溫度、進食和繁殖有密切關(guān)系。）

Ventrolateral preoptic nucleus[edit]

The?ventrolateral preoptic nucleus, or intermediate nucleus, is adjacent to the medial preoptic nucleus. It also mediates non-REM sleep onset.

Preoptic periventricular nucleus[edit]

The preoptic periventricular nucleus is located along the midline and is medial to the medial preoptic nucleus.