Mechanisms of Magnetoreception

菲利普斯博士将使用行为技术来研究东太平洋鳗(Notophthalmus Viridesens)对地球磁场的探测和利用。以前的工作已经表明，蝾螈用来进行岸上定向的磁罗盘受到光波长的影响。对磁罗经方向与波长相关的测量将扩展到近紫外光，以更好地表征对磁罗盘做出贡献的视觉输入。此外，到达松果体器官和眼睛的光的波长将被选择性地改变，以确定依赖光的磁罗盘是否位于这两个感光器官之一。为了调查磁场在寻的中的作用，更具体地说，在寻的所需的“地图”或地理位置意义上，将进行实验，以研究改变光的波长和操纵磁场的特定分量(即倾角和总强度)对寻的方向的影响。这项研究将有助于更好地了解松果体的功能以及脊椎动物大脑对感觉信息的处理。此外，从这项研究中获得的信息将有助于表征两栖动物的视觉系统在多大程度上已经专门化，以执行特定的感觉功能(即探测地球磁场)。对这些特殊感觉功能的更全面的了解将使人们有可能确定两栖动物的视觉系统何时可以作为研究包括人类在内的其他脊椎动物的视觉过程的合适模型系统。最后，研究两栖动物在远距离移动时使用的定向策略将有助于更好地理解脊椎动物的大脑如何处理空间信息。

Dr. Phillips will use behavioral techniques to examine the detection and use of the earth's magnetic field by the eastern newt (Notophthalmus viridescens). Previous work has shown that the magnetic compass used by newts for shoreward orientation is influenced by the wavelength of light. Measurements of the wavelength-dependence of magnetic compass orientation will be extended into the near-ultraviolet to better characterize the visual inputs that contribute to the magnetic compass. In addition, the wavelength of light reaching the pineal organ and eyes will be selectively altered to find out if the light- dependent magnetic compass is located in one of these two photoreceptive organs. To investigate the involvement of the magnetic field in homing and, more specifically, in the "map" or geographic-position sense that is required for homing, experiments will be carried out to examine the effects of varying the wavelength of light and of manipulating specific components of the magnetic field (i.e., the dip angle and total intensity) on homing orientation. This research will contribute to a better understanding of the function of the pineal and of the processing of sensory information by the brain of vertebrates. In addition, the information gained from this research will help to characterize the extent to which the visual system of amphibians has become specialized to perform specific sensory functions (i.e., detection of the earth's magnetic field). A more complete understanding of these specialized sensory functions will make it possible to determine when the amphibian visual system can serve as an appropriate model system for studying visual processes that occur in other vertebrates, including humans. Finally, investigation of the strategies used by amphibians to orient during long-distance movement will contribute to a better understanding of how the brain of vertebrates processes spatial information.