Simulation of confined diffusion in a potential, V(r). (A) Profiles of the four potential functions used in this study. (B) MSD versus time plots. (C) Representative single-particle trajectories shown in order of decreasing steepness of potential. White circles denote the potential center of each trajectory. Parameters: hard-wall potential, D = 0.012 μm2/s, rc = 0.347 μm; spring potential, D = 0.010 μm2/s, V0 = 0.17; cone potential, D = 0.012 μm2/s, V0 = 0.123; r4 potential, D = 0.011 μm2/s, V0 = 0.99; for all computations, frame rate was 10 Hz with >4000 time steps sampled.