Schematic representation of our random walk model with environmental state-dependent dynamics. Schematic representation of our random walk model with environmental state-dependent dynamics. In our model, the sojourn time distribution ψΓ(t) of a random walker is dependent on environmental state variables, Γ. The probabilistic dynamics of this random walker model can be described by Eq. 2 in the continuum limit. Sanggeun Song et al. PNAS doi:10.1073/pnas.1900239116 ©2019 by National Academy of Sciences