Tracking Freely Walking Flies: A Method to Assess Locomotion in Drosophila

This protocol is an excerpt from Sun and Chen, A Novel Method to Model Chronic Traumatic Encephalopathy in Drosophila, J. Vis. Exp. (2017).

1. Video-assisted Movement Tracking

1. Fill a 6-cm-diameter Petri dish with transparent silicon elastomer to make the tracking arena. Leave a 3 mm space between the silicon and the dish lid to allow the flies to walk freely but not fly.
2. Anesthetize four flies from either the sham or treated group each time and place them in the arena. Leave the flies at 22 °C for 1 h.
3. Position a Charge-Coupled Device (CCD) camera above the arenas and record for 5 min.
4. Analyze the recorded movement trajectories using Ctrax software (freely available from Caltech). Export the tracked data in a programming language (e.g., Matlab)-compatible format and analyze the data based on distance traveled per frame. Calculate the mean walking distance for each fly and combine it with all other recorded flies/group to obtain a mean cumulative distance travelled by the population of files in the same group.