In collaboration with one of our users, we have developed a novel measure of circling behavior. The analysis is based on spectral methods of analysis — similar to a sound spectrogram — applied to the animal’s path. In the image below, a drug has been administered at the 1800-second mark and animal begins circling. The animal’s locomotion energy starts to concentrate into a small band of frequencies, as shown in the spectrogram (colormap). As a result, the circling index, which integrates over all frequencies, rises. LimeLight allows the user to zoom in on any portion of the graphs below, select a point in the graph and display the animal’s behavior at that point, and export the circling index for multiple trials.