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Last week’s PLoS ONE paper, Analysis of the Trajectory of Drosophila melanogaster in a Circular Open Field Arena, is the subject of the newest Journal Club. It is an interesting methods paper, showing the way a camera and some math can be used for a much more sophisticated analysis of animal behavior than it has traditionally been done.

The Journal Club this week is being led by Bjoern Brembs from the Institute of Biology – Neurobiology, Freie Universitat Berlin. You may be familiar with his name because Bjoern also writes a science blog.

The group has now posted some initial commentary, in particular a list of questions. It is now up to YOU to go and add your voice to the Journal Club – answer the questions if you can, or ask new questions, or just post a brief comment.

Here is the abstract, and you go read the entire paper, rate, comment, annotate, blog about and send trackbacks:


Obtaining a complete phenotypic characterization of a freely moving organism is a difficult task, yet such a description is desired in many neuroethological studies. Many metrics currently used in the literature to describe locomotor and exploratory behavior are typically based on average quantities or subjectively chosen spatial and temporal thresholds. All of these measures are relatively coarse-grained in the time domain. It is advantageous, however, to employ metrics based on the entire trajectory that an organism takes while exploring its environment.

Methodology/Principal Findings

To characterize the locomotor behavior of Drosophila melanogaster, we used a video tracking system to record the trajectory of a single fly walking in a circular open field arena. The fly was tracked for two hours. Here, we present techniques with which to analyze the motion of the fly in this paradigm, and we discuss the methods of calculation. The measures we introduce are based on spatial and temporal probability distributions and utilize the entire time-series trajectory of the fly, thus emphasizing the dynamic nature of locomotor behavior. Marginal and joint probability distributions of speed, position, segment duration, path curvature, and reorientation angle are examined and related to the observed behavior.


The measures discussed in this paper provide a detailed profile of the behavior of a single fly and highlight the interaction of the fly with the environment. Such measures may serve as useful tools in any behavioral study in which the movement of a fly is an important variable and can be incorporated easily into many setups, facilitating high-throughput phenotypic characterization.


  1. #1 Coturnix
    October 30, 2007