RUI: Role of the Intergeniculate Leaflet in Circadian Rhythms

昼夜节律是哺乳动物的基本生物学过程，其将生物体的激素、代谢和生理活动同步到24小时周期中。主要的昼夜节律起搏器，也被称为生物钟，存在于大脑中下丘脑底部的视交叉上核中的神经元集合中。这个起搏器接收来自眼睛的输入，以传达有关太阳日的亮/暗周期的信息，用于设置时钟的时间，但起搏器也接收来自其他功能不清楚的大脑区域的输入。本项目旨在确定这些输入之一的作用，从丘脑的膝状体小叶，对仓鼠的生物钟的计时性能。本计画将利用行为学与解剖学的方法来研究膝状体间叶在生理活动节律中的角色。该项目预计将证明，从膝状体间叶到时钟的输入在夜间是紧张性抑制的，并且当这种输入被阻断时，起搏器能够更快地重置时间以响应白昼长度的变化。该项目还将展示生物体如何能够防止来自星星和月亮的低水平光线改变起搏器的时间。该项目的结果对于我们了解生物如何适应环境中的季节性日光变化非常重要。最后，该项目将为本科生和研究生提供重要的科学培训，其中许多人将是女性和代表性不足的少数民族。

Circadian rhythms are fundamental biological processes in mammals that synchronize the hormonal, metabolic and physiological activities of the organism into a twenty-four hour cycle. The primary circadian pacemaker, also called the biological clock, is found in a collection of neurons located in the suprachiasmatic nuclei at the base of the hypothalamus in the brain. This pacemaker receives input from the eye to convey information about the light/dark cycle of a solar day that is used to set the time of the clock, but the pacemaker also receives input from other brain regions whose function is unclear. This project aims to determine the role of one of these inputs, from the intergeniculate leaflet of the thalamus, on the timekeeping properties of the biological clock in hamsters. This project will use behavioral and anatomical approaches to study the role of the intergeniculate leaflet in circadian activity rhythms. This project is expected to demonstrate that the input from the intergeniculate leaflet to the clock is tonically inhibitory at night, and that when this input is blocked, the pacemaker is capable of a much more rapid resetting of time in response to changes in daylength. This project will also demonstrate how organisms are able to prevent low levels of light from stars and the moon from shifting the timing of the pacemaker. The results of this project are very important for our understanding of how organisms adapt to seasonal daylight changes in their environment. Finally, this project will provide crucial training in the sciences to undergraduate and graduate students, many of whom will be female and underrepresented minorities.