In the T-maze phototaxis assay, flies are faced to a light/dark choice. Briefly, flies had to choose whether to go to a bright or a dark tube, respectively. There are several possible configurations of this paradigm. In some of them, flies are tested individually (Figure 1 obtained from (Bourg & Badia, 1995)), while in others such as the one we use, flies are tested in groups.

Figure 1. Single fly T-Maze phototaxis assay.

Our T-Maze is an adaptation from the paradigm used in olfactory conditioning (Tully & Quinn, 1985). The training tube in our case was substituted with an entrance tube, where flies adapt to the initial conditions, and the collection tubes differ only in their illumination conditions. The differences between collection tubes can be generated with LEDs placed at the end of the tubes, or by making one of them transparent and the other opaque (Figure 2).

Figure 2. T-Maze phototaxis assay for group tests.

The main advantage of the T-Maze over the Benzer Countercurrent paradigm is that negative and positive phototaxis could be tested at the same time.

For a detailed protocol for our T-Maze paradigm pleas go here

References

Bourg, E. Le, & Badia, J. (1995). Decline in photopositive tendencies with age in Drosophila melanogaster (Diptera: Drosophilidae). Journal of Insect Behavior, 8(6), 835–845.

Tully, T., & Quinn, W. G. (1985). Classical conditioning and retention in normal and mutant Drosophila melanogaster. Journal of Comparative Physiology. A, Sensory, Neural, and Behavioral Physiology, 157(2), 263–77.