Fig. 4.

Mapping the Relative Resilience of a Regulatory Program. Graphical representation of the estimated probability of occurrence (State Transition Matrix) of state transitions resulting in a return to a given attractor versus an escape to the neighboring attractor. Markov Chain Monte Carlo simulations repeated 1000 times for each of the 36 possible initial states, were conducted with 5% random biological noise applied to an unperturbed HPA axis at rest (wild type) (a), to conditions of persistent environmental stress (b), and under therapeutic blockade of R (c). Results suggest that conditions of persistent stress facilitate the transition to a chronic HPA dysregulation while downregulation of R significantly destabilizes the latter favoring a return to normal HPA rhythm