Schmid College of Science and Technology, Chapman University, Orange, CA, USA.
Sci Rep. 2021 Jul 29;11(1):15481. doi: 10.1038/s41598-021-94927-6.
For many species, parental care critically affects offspring survival. But what drives animals to display parental behaviours towards young? In mammals, pregnancy-induced physiological transformations seem key in preparing the neural circuits that lead towards attraction (and reduced-aggression) to young. Beyond mammalian maternal behaviour, knowledge of the neural mechanisms that underlie young-directed parental care is severely lacking. We took advantage of a domesticated bird species, the Japanese quail, for which parental behaviour towards chicks can be induced in virgin non-reproductive adults through a sensitization procedure, a process that is not effective in all animals. We used the variation in parental responses to study neural transcriptomic changes associated with the sensitization procedure itself and with the outcome of the procedure (i.e., presence of parental behaviours). We found differences in gene expression in the hypothalamus and bed nucleus of the stria terminalis, but not the nucleus taeniae. Two genes identified are of particular interest. One is neurotensin, previously only demonstrated to be causally associated with maternal care in mammals. The other one is urocortin 3, causally demonstrated to affect young-directed neglect and aggression in mammals. Because our studies were conducted in animals that were reproductively quiescent, our results reflect core neural changes that may be associated with avian young-directed care independently of extensive hormonal stimulation. Our work opens new avenues of research into understanding the neural basis of parental care in non-placental species.
对于许多物种来说，亲代抚育对后代的生存至关重要。但是，是什么驱使动物对幼崽表现出亲代行为呢？在哺乳动物中，妊娠引起的生理变化似乎是准备导致对幼崽产生吸引力（和减少攻击性）的神经回路的关键。除了哺乳动物的母性行为之外，对基础幼崽导向亲代护理的神经机制的了解还严重缺乏。我们利用一种驯化鸟类，即日本鹌鹑，通过敏化程序可以在处女非生殖成年期诱导其对雏鸡的亲代行为，而该过程在所有动物中并不有效。我们利用亲代反应的变化来研究与敏化程序本身以及程序结果（即存在亲代行为）相关的神经转录组变化。我们发现下丘脑和终纹床核中的基因表达存在差异，但核带不明显。鉴定出的两个基因特别有趣。一个是神经降压素，以前仅在哺乳动物中被证明与母性行为有关。另一个是促皮质素 3，在哺乳动物中被证明会影响幼崽导向的忽视和攻击。由于我们的研究是在生殖静止的动物中进行的，因此我们的研究结果反映了与鸟类幼崽导向护理相关的核心神经变化，而与广泛的激素刺激无关。我们的工作为理解非胎盘物种的亲代护理的神经基础开辟了新的研究途径。
