FB Biologie, Chemie, Pharmazie, Institut für Biologie-Neurobiologie, Freie Universität Berlin, Berlin, Germany. J.C
PLoS One. 2012;7(8):e42247. doi: 10.1371/journal.pone.0042247. Epub 2012 Aug 9.
Insects have been among the most widely used model systems for studying the control of locomotion by nervous systems. In Drosophila, we implemented a simple test for locomotion: in Buridan's paradigm, flies walk back and forth between two inaccessible visual targets [1]. Until today, the lack of easily accessible tools for tracking the fly position and analyzing its trajectory has probably contributed to the slow acceptance of Buridan's paradigm.
METHODOLOGY/PRINCIPAL FINDINGS: We present here a package of open source software designed to track a single animal walking in a homogenous environment (Buritrack) and to analyze its trajectory. The Centroid Trajectory Analysis (CeTrAn) software is coded in the open source statistics project R. It extracts eleven metrics and includes correlation analyses and a Principal Components Analysis (PCA). It was designed to be easily customized to personal requirements. In combination with inexpensive hardware, these tools can readily be used for teaching and research purposes. We demonstrate the capabilities of our package by measuring the locomotor behavior of adult Drosophila melanogaster (whose wings were clipped), either in the presence or in the absence of visual targets, and comparing the latter to different computer-generated data. The analysis of the trajectories confirms that flies are centrophobic and shows that inaccessible visual targets can alter the orientation of the flies without changing their overall patterns of activity.
CONCLUSIONS/SIGNIFICANCE: Using computer generated data, the analysis software was tested, and chance values for some metrics (as well as chance value for their correlation) were set. Our results prompt the hypothesis that fixation behavior is observed only if negative phototaxis can overcome the propensity of the flies to avoid the center of the platform. Together with our companion paper, we provide new tools to promote Open Science as well as the collection and analysis of digital behavioral data.
昆虫一直是用于研究神经系统控制运动的最广泛使用的模型系统之一。在果蝇中，我们实现了一个简单的运动测试：在布瑞丹范式中，果蝇在两个无法到达的视觉目标之间来回走动[1]。直到今天，缺乏易于访问的工具来跟踪果蝇的位置并分析其轨迹，这可能导致布瑞丹范式的接受速度较慢。
方法/主要发现：我们在这里介绍了一个开源软件包，用于跟踪在同质环境中行走的单个动物（Buritrack）并分析其轨迹。Centroid Trajectory Analysis（CeTrAn）软件是在开源统计项目 R 中编写的。它提取了十一个指标，并包括相关分析和主成分分析（PCA）。它旨在易于根据个人需求进行定制。与廉价的硬件相结合，这些工具可以很容易地用于教学和研究目的。我们通过测量成年黑腹果蝇（其翅膀被剪掉）在存在或不存在视觉目标的情况下的运动行为，展示了我们软件包的功能，并将后者与不同的计算机生成的数据进行比较。轨迹分析证实，果蝇具有中心回避性，并且表明不可访问的视觉目标可以改变果蝇的方向，而不会改变它们的整体活动模式。
结论/意义：使用计算机生成的数据对分析软件进行了测试，并设置了一些指标的机会值（以及它们的相关性的机会值）。我们的结果提示了一个假设，即只有当负趋光性能够克服果蝇避免平台中心的倾向时，才会观察到固定行为。结合我们的姊妹篇论文，我们提供了新的工具，以促进开放科学以及数字行为数据的收集和分析。
