Before revision:  The critical vesicle-to-spine diameter ratio predicted by our analysis , at which there is a transition from unidirectional to bidirectional motion, is consistent with experimental observations of vesicle trajectories in the literature.
After revision:  The critical vesicle-to-spine diameter ratio , at which there is a transition from unidirectional to bidirectional motion, is consistent with experimental observations of vesicle trajectories in the literature.