NEUROSENSORY MECHANISMS OF ORIENTATION TO GEOMAGNETISM

有证据表明，某些动物能探测到并确定自己的方位， 地球的磁场这种能力可以在归航的上下文中使用， 寻找配偶，寻找食物来源虽然 生物传感器的存在可以转换地磁， 从不同动物的定向反应中推断， 已知的机制转导的地磁能量到 任何多细胞动物的神经系统。 人们发现了一种动物，它有两个不寻常的特征， 一个了解物理/生物学基础的机会 用于地磁感应。海洋裸鳃类软体动物Tritonia diomedia 通过适当地定向来响应地球磁场， 其他提示不可用。其次，在最近的实验中， 在动物的大脑中发现了一对可重新识别的神经元， 对周围磁场方向的变化作出反应 电脉冲 在这个建议中，实验描述了行为，神经元 电路和单个神经元水平，旨在（i）建立 地磁感觉系统在行为水平上的调整， 适当的可重新识别的神经元，（ii）进一步跟踪神经元 将这种感觉输入耦合到相关运动控制的电路 使用电生理学技术，和（iii）确定细胞和 分子水平上的磁能转换机制 神经系统信号。

Evidence indicates that certain animals detect and orient themselves to the earth's magnetic field. This capacity may be used in the context of homing, finding mates, and locating food sources, for instance. Although the existence of biosensory apparatus for transducing geomagnetism can be inferred from the orienting responses of diverse animals, little is yet known of the mechanisms of transduction of geomagnetic energy into the nervous system of any multicellular animal. An animal has been found which has two unusual features and which provides an opportunity to achieve an understanding of the physical/biological basis for the geomagnetic sense. The marine nudibranch mollusc, Tritonia diomedia response to the earth's magnetic field by orienting appropriately when other cues are unavailable. Secondly, in recent experiments, a symmetrical pair of re-identifiable neurons in the animal's brain have been found which respond to changes in the direction of the ambient magnetic field by firing electrical impulses. In this proposal, experiments are described at the behavioral, neuronal circuitry, and single neuron level that are designed to (i) establish the tuning of the geomagnetic sensory system at the behavioral level and in appropriate re-identifiable neurons, (ii) trace further the neural circuitry that couples this sensory input to the relevant motor control using electrophysiological techniques, and (iii) determine cellular and molecular level mechanisms underlying the transduction of magnetic energy into nervous system signals.