Environmental Statistics and Optimal Regulation
Figure 5
In a rapidly changing environment, the value of memory peaks at intermediate measurement noise.
For a quadratic cost function and environmental changes on timescales comparable to cellular response, the dimensionless ratio determines the preference among different regulatory strategies [see Eq. (11)]. High relative measurement noise (
, right column) leads to a preference for constitutive response; low relative measurement noise (
, left column) produces a preference for naive response to the present measurements; and the intermediate case (
, middle column) produces a preference for dynamic Bayesian inference that takes into account both present and past measurements. In the heat maps (bottom row), blue represents high levels of enzyme and green represents low.