Figure 6
An example result based on a model of synaptic competition among axons, tSCs, and vacancies with different constant transition probabilities derived from the area ratios at P3 of the NMJs. Simulations carried out using the same configuration as described in Fig. 3, but the final ratios of tSCs, vacancies and axons are set to be 0.57, 0.18, and 0.25, respectively, which are the ratios at P3 of the NMJs. (a) Initially, 9 different axons, tSCs and vacancies form their contact sites randomly on a muscle fiber with the initial ratio of their total contact areas (axons:tSCs:vacancies), which is about 30:16:54 as Fig. 4. (b–h) The competition among axons, tSCs, and vacancies with their constant transition probabilities shows elimination of multiple contact sites formed by different axons, tSCs, and vacancies at different iterations of the simulation (100, 200, 300, 700, 1500, 3400, and 4100 iterations, respectively). (i) When the simulation is at 10,400 iterations, the competition leads to a complete synapse elimination with tSC and vacant sites present demonstrating that optimal transition probabilities reliably simulate synapse elimination. (j) The number of different types of axons in the endplate reduces sharply as the iteration proceeds. (k) Change in the ratios of the contact areas formed by tSCs (green), vacancies (black), and 9 different axons (colors different from green and black) as the simulation based on the stochastic model of tSC and vacancy mediated synapse elimination proceeds. Inset: the distribution of the least number of iterations when synapse elimination is complete from 100 repeated simulations.
