Pubertal Brain Development: Hormones & Circadian Entrainment

大多数物种至少经历两个生命阶段，即早期生长和随后的成熟生殖阶段。在哺乳动物中，这些阶段与被定义为青春期的主要生理、神经和行为变化时期相关联。与成熟相关的激素变化会引起大脑和行为的重要变化。然而，很少有人注意到在青春期变化期间发生的事情，这是这一时期所特有的。这些变化之一是睡眠/觉醒周期的时间延迟，该项目在一种缓慢发育的昼夜活动啮齿动物（degu）和一种快速发育的普通实验室动物（大鼠）中进行了建模。该项目将确定青春期激素变化对睡眠/觉醒周期时间改变的作用，通过删除和替换它们。它还将确定神经变化是否发生在协调所有日常节奏的大脑区域，或者通过检查昼夜不停地收集和分析的组织切片来确定这些变化是否发生在接收这些中枢信号的区域。最后，该项目将通过研究不同条件下日常行为的变化来研究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几乎影响了生理学的所有方面，这些发现将有助于更好地了解哺乳动物在青春期的生理和行为状态。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。学生和项目主任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。该项目还将支持开发从动物身上收集的日常活动和其他节律数据库，以便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.