Collaborative Research: Role of Neuronal Activity in Visually Guided Escape Behaviors

避免碰撞是生存的关键，被认为与视觉引导逃逸有关的感觉和运动神经元的活动已经在几个物种中进行了研究。然而，视觉信息在感觉区域的处理导致逃避的准备和执行的机制仍然知之甚少。目前的项目通过研究自由行为的蝗虫对模拟物体在碰撞过程中接近时的逃逸进行研究，并将这些研究与对受限制和自由移动的动物的神经活动的电生理记录相结合来解决这个问题。之所以对蝗虫进行研究，是因为参与产生逃逸行为的神经路径具有良好的特征，并且可以进行神经生理学研究。该项目将使用多学科方法，结合行为学、神经生理学和计算机工程学，将逃避行为的产生与单个神经细胞活动中视觉刺激的编码联系起来。加比亚尼和他的合作者将首先描述蝗虫在碰撞过程中接近物体时，不同阶段逃生跳跃的时间是如何取决于接近物体的速度和大小的。当动物从模拟的物体或隐约可见的刺激中跳出来时，将用高速视频系统拍摄它们。接下来，在受限制的动物中，对隐约可见敏感的神经元的电活动将被检测，该神经元将信息从感觉传递到蝗虫中枢神经系统中的运动中心，以应对类似的刺激条件。在这一过程中被认为是关键的一个神经元，下降对侧运动检测器(DCMD)神经元，将被详细研究。在这些神经生理学研究的同时，该项目的计算机工程师将开发一种能够由蝗虫携带的微型数字无线记录和传输系统。该系统将从植入昆虫神经系统的电极传输多达8个通道的神经元数据，包括来自受限制蝗虫研究的DCMD细胞的信号。这个小装置将被固定在蝗虫的背部，以实时监测逃生跳跃过程中的神经活动。在单独的实验中，还将监测导致跳跃产生的肌肉活动。综上所述，本研究将首次对自由行为动物视觉引导逃逸行为的刺激参数、感觉神经元活动和运动阶段之间的关系进行定量研究，从而对其感觉和运动成分之间的联系有一个完整的理解。这个项目在研究界之外还有更广泛的影响。加比亚尼博士已经并将继续与他实验室里的一名高中科学教师密切合作，开发有关行为的神经控制以及计算机工程与生物学的整合的高中科学课程模块。该项目还将支持对几名研究生进行跨学科培训。

Avoidance of collisions is critical to survival and the activity of sensory and motor neurons thought to be involved in visually-guided escape has been studied in several species. However, the mechanisms by which visual information processed in sensory areas leads to the preparation and execution of escape remains poorly understood. The current project addresses this question by studying escape of freely behaving locusts in response to simulated objects approaching on a collision course and by coupling these studies with electrophysiological recordings of neuronal activity both in restrained and freely moving animals. The locust will be studied because the neural pathways involved in generating escape behavior are well characterized and are accessible for neurophysiological investigation. The project will use a multi-disciplinary approach, combining behavior, neurophysiology and computer engineering to relate the generation of escape behaviors to the coding of visual stimuli in the activity of individual nerve cells. Gabbiani and his collaborators will first characterize how the timing of various stages of escape jumps elicited in locusts by the approach of an object on a collision course depends on the speed and size of the approaching object. Animals will be filmed with a high speed-video system as they jump from the simulated approach of objects, or looming stimuli. Next, in restrained animals, the electrical activity of neurons sensitive to looming, which relay information from sensory to motor centers in the locust central nervous system, will be examined in response to similar stimulus conditions. One individual neuron thought to be critical in this process, the descending contralateral motion detector (DCMD) neuron, will be studied in detail. In parallel to these neurophysiological studies, computer engineers on the project will develop a miniature digital wireless recording and transmission system able to be carried by the locust. This system will transmit up to eight channels of neuronal data from electrodes implanted in the insect's nervous system, including signals from the DCMD cell studied in the restrained locust. The small device will affixed to the back of locusts to monitor nervous activity in real time during escape jumps. In separate experiments, the muscular activity leading to the generation of jumps will be monitored as well. Taken together, this study will for the first time investigate quantitatively the relation between stimulus parameters, the activity of sensory neurons and the motor stages of a visually guided escape behavior in freely behaving animals, thus leading to an integrated understanding of the connection between its sensory and motor components. This project also has a broader imact beyond the research community. Dr. Gabbiani has worked, and will continue to work, closely with a high school science teacher in his laboratory to develop high school science curriculum modules on the neural control of behavior and the integration of computer engineering with biology. The project will also support the interdisciplinary training of several graduate students.