Pubertal Brain Development: Hormones & Circadian Entrainment

大多数物种至少经历两个生命阶段，早期生长，随后是成熟的生殖阶段。在哺乳动物中，这些阶段是由一个主要的生理、神经和行为变化时期联系在一起的，这个时期被称为青春期。与成熟相关的荷尔蒙变化会引起大脑和行为的重要变化。然而，很少有人注意到青春期特有的变化期间发生了什么。其中一个变化是睡眠/觉醒周期的时间延迟，这个项目在一种发育缓慢的白天活动的啮齿动物德古鼠和一种发育较快的普通实验动物老鼠身上进行了建模。该项目将通过移除和替换青少年激素来确定青春期激素变化对睡眠/觉醒周期改变时间的作用。它还将通过检查昼夜收集和分析的组织切片，确定神经变化是发生在协调所有日常节奏的大脑区域，还是发生在接收中枢信号的区域。最后，该项目将通过检查青少年在不同条件下的日常行为变化来检查不同照明水平对青少年变化的影响。由于大脑日常计时机制的变化影响着生理学的几乎所有方面，这些发现将使我们对哺乳动物青春期的生理和行为状态有更深入的了解。该项目每年将支持一名研究生和至少两名本科生的研究活动。学生和项目主管还提供与青少年睡眠/觉醒变化相关的学术和社区学习机会。该项目还将支持从动物身上收集日常活动和其他节律的数据库的开发，该数据库可以与该领域的其他研究人员共享。

Most species undergo at least two life phases, early growth followed by a mature reproductive stage. In mammals these phases are linked by a period of major physiological, neural and behavioral change defined as adolescence. Hormonal changes associated with maturation cause important changes in the brain and behavior. Little attention, however, has been paid to what happens during the period of adolescent change that is unique to that period. One of these changes is a delay in the timing of sleep/wake cycle that this project models in a slow-developing diurnal rodent, the degu, and a faster-developing common lab animal, the rat. This project will determine the role of adolescent hormone changes on the altered timing of the sleep/wake cycle by removing and replacing them. It will also determine whether the neural changes are occurring in the area of the brain that coordinates all daily rhythms, or if the changes are in areas that receive those central signals by examining slices of the tissue collected and analyzed around the clock. Lastly, the project will examine the impact of different lighting levels on the adolescent changes by examining changes in daily behavior under different conditions. Because changes in the daily timing mechanism of the brain impacts nearly all aspects of physiology, these findings will lead to a greater appreciation of the physiological and behavioral state of mammals during adolescence. The project will support the research activity of a graduate student and at least two undergraduates each year. The students and the project director also provide academic and community learning opportunities related to adolescent sleep/wake changes. The project will also support the development of a data base of daily activity and other rhythms collected from animals that can be shared with other researchers in the field.