Movie 3

Exemplary tracks of control cells and tetanus toxin-treated cells. In this movie, six pairs of tracks are shown, each consisting of length-matched tracks recorded under control conditions and following incubation with tetanus toxin. Note that under control conditions, tracks are highly directed and typically elongated, though they may also comprise short phases or random, to-and-fro movement. Following treatment with tetanus toxin (TeNT), cells show very little, if any, directional persistence, and individual steps of each track appear more or less randomly oriented. Consequently, the net displacement from the first to the last time point is small as compared to controls.
As the movie does not allow visualizing the true three-dimensional structure of the tracks, we rotated tracks such that their projection to the screen maximises their visible length (see yellow box in the overview scheme at the top right corner for orientation). Treatment condition and three-dimensional track lengths (in μm) are indicated in the stills preceding movie sequences. In some sequences, centres of mass of essentially immobile cells can be seen and may serve as a reference.
The net displacements of these length-matched tracks were as follows (all in μm; controls vs TeNT-treated): 12.8 vs 1.9; 5.1 vs 1.4; 4.4 vs 1.1; 14.5 vs 0.9; 13.2 vs 1.2; 14.9 vs 6.8.