Neural mechanisms of social status during adolescence

在包括人类在内的动物中，赢得竞争会增加在未来比赛中获胜的机会，而失败则会增加未来再次失败的机会。这些影响的产生是因为赢和输的经历对大脑有不同的影响。这些发现无法解释的是，个体是如何从失败转变为成功的。在青少年时期尤其如此，因为这个时期的人缺乏竞争经验，更容易失败。一种特殊类型的行为策略，社会警惕，可能是促进这种转变的关键机制。社会警惕性包括对潜在威胁个体的回避和观察的结合。在这个项目中，研究小组将测试青春期睾酮分泌的增加是否会促进男性从社会警觉到更自信的攻击行为的转变。在成年人中，获胜后睾丸激素的短期增加在促进赢家效应中起着关键作用。研究人员预测，青春期睾丸激素的分泌会使促进社会警觉性的神经回路变得不敏感。为了解决这个问题，这个项目将确定睾丸激素在青春期是否会改变神经回路中的神经元活动，这些神经回路控制着社会警觉性，以及攻击性遭遇中使用的防御和攻击发声。加州大学戴维斯分校是一所西班牙裔服务机构，在支持包容性STEM文化以扩大影响和增加发现方面有着良好的记录。对这项研究的支持将为STEM历史上的弱势群体提供培训机会，并通过开放日活动增加社区参与。这个项目整合了社会行为的行为、神经内分泌和生理层面的分析。先前的研究表明，在尾纹床核（BNST）中起作用的催产素会增加社会警觉行为，而社会压力会增加催产素神经元的活动。一个关键的假设是，青春期睾丸激素的激增重新编程了脑脊液中的催产素神经元，使其对社会压力不那么敏感。社会警觉性依赖于催产素，在青少年中比成年人更普遍。这项研究将首先测试青春期睾丸激素的增加是否会降低男性和女性因压力引起的警惕性。我们将探讨应激对催产素神经元长时程增强（LTP）的影响，以及应激对LTP的影响是否受到青春期睾酮暴露的调节。在大鼠的海马体和斑胸草雀的鸣叫控制系统中，睾丸激素在青春期起到降低LTP的作用。最后，将通过观察领地形成过程中的攻击行为和使用特征明确的自信和被动发声来研究青春期睾酮对领地形成的影响。这些研究的结果将为促进脊椎动物物种之间社会过渡的神经回路提供重要的见解。该项目还将产生新的工具，包括将在brainmaps.org上发布的加州青少年老鼠大脑图谱。该奖项反映了美国国家科学基金会的法定使命，并通过基金会的智力价值和更广泛的影响审查标准进行了评估，认为值得支持。

In animals including humans, winning a competitive encounter increases the chances of winning in future contests while losing increases the chance losing again in the future. These effects occur because the experience of winning and losing have different effects on the brain. What these discoveries do not explain, is how individuals can transition from losing to winning. This is especially true during adolescence, when individuals have less competitive experience and are more likely to lose. A specific type of behavioral strategy, social vigilance, may be a key mechanism for facilitating this transition. Social vigilance involves a combination of avoidance and observation of potentially threatening individuals. In this project, the research team will test whether increased testosterone secretion during adolescence facilitates a transition from social vigilance to more assertive aggressive behaviors in males. In adults, short term increases in testosterone after winning play a key role in facilitating winner effects. The researchers predict that the testosterone secretion during adolescence desensitizes neural circuits that promote social vigilance. To address this question this project will determine whether testosterone acts during puberty to alter the activity of neurons within neural circuits that control social vigilance as well as defensive and offensive vocalizations used in aggressive encounters. The University of California at Davis is a Hispanic Serving Institution with a strong track record of supporting an inclusive STEM culture to broaden impact and increase discovery. Support of this research will provide training opportunities for historically disadvantaged groups in STEM and increase community engagement via open house events.This project integrates behavioral, neuroendocrine, and physiological levels of analysis of social behavior. Previous work shows that oxytocin acting in the bed nucleus of the stria terminalis (BNST) increases social vigilance behavior, and that social stress increases the activity of oxytocin neurons. A key hypothesis is that the pubertal surge of testosterone reprograms oxytocin neurons in the BNST to be less sensitive to social stress. Social vigilance is oxytocin dependent, and more prevalent in juvenile males than adults. This research will first test whether increased testosterone during puberty reduces stress-induced vigilance in males and females. The effects of stress on long term potentiation (LTP) of oxytocin neurons will be examined and whether the effects of stress on LTP are modulated by pubertal testosterone exposure. In the rat hippocampus and the zebra finch song control system testosterone acts during puberty to reduce LTP. Finally, the effects of pubertal testosterone on territory formation will be studied by observing aggressive behaviors and the use of well characterized assertive and passive vocalizations during territory formation. Results from these studies will provide important insights into the neural circuits that facilitate social transitions that occurs across vertebrate species. This project will also generate new tools, including a brain atlas of the adolescent California mouse brain which will be hosted on brainmaps.org.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.