Fig. 9

The ACC and its analyzer-effector function in selecting the best strategy. A During stress, the ACC assesses the gap between the probability distributions of ‘attainable states’ and ‘goal states’ in a search for plausible strategies or “policies” that constitute a menu of options. Such a gap or divergence is called a Kullback-Leibler divergence (DKL). The greater the relative risk represented by the divergence, the greater the uncertainty about which policy to choose leading to greater amygdalar activation. B Each policy represents a different relative risk (DKL). C Based upon the risk probability distribution, the ACC analyzes each strategy i (i = 1,2, …, n) for the probability that it will reduce negative prediction error and effect an attachment solution to the current separation challenge and thus ensure wellbeing. In this graphic, all probabilities are relatively low. Thus, uncertainty persists about the answer to the potential separation challenge. This can lead to a separation threat-based stress response due to a high level of uncertainty and the intolerance that ensues causing entropic strain with metabolic wear and tear in the system. From: Peters et al, 2017, p. 182 (open access) [116]. "Reprinted from, Progress in Neurobiology, 156. Peters A, McEwen BS, Friston K. Uncertainty and stress: Why it causes diseases and how it is mastered by the brain. P. 182, 2017, under Creative Commons Attribution Non-Commercial No Derivatives license permission from Elsevier via STM guidelines