Chronic Stress Causes Frontostriatal Reorganization and Affects Decision-Making

Abstract

The ability to shift between different behavioral strategies is necessary for appropriate decision-making. Here, we show that chronic stress biases decision-making strategies, affecting the ability of stressed animals to perform actions on the basis of their consequences. Using two different operant tasks, we revealed that, in making choices, rats subjected to chronic stress became insensitive to changes in outcome value and resistant to changes in action-outcome contingency. Furthermore, chronic stress caused opposing structural changes in the associative and sensorimotor corticostriatal circuits underlying these different behavioral strategies, with atrophy of medial prefrontal cortex and the associative striatum and hypertrophy of the sensorimotor striatum. These data suggest that the relative advantage of circuits coursing through sensorimotor striatum observed after chronic stress leads to a bias in behavioral strategies toward habit.

Effect of chronic stress during adolescence in prefrontal cortex structure and function

“…Chronic stressor agents cause a decrease in the amount of labeled PNN + neurons both in the medial and orbital regions of the prefrontal cortex. Other studies had already demonstrated the effects of chronic stress on the morphology of pyramidal neurons, such as structural modifications on dendritic arborization and decrease in the number of dendritic spines [18,20], probably due to an increase in the number of excitatory amino acids (glutamate) induced by greater amounts of glucocorticoids in the bloodstream [50,56,63]. Chronic stress also increased the expression of genes that regulate neuronal metabolism and synaptic changes in glutamate receptors [10,73].…”

“…Chronic stress also interferes with the function of the sympathetic nervous system and the HPA axis [10,14,52]. However, since several studies have demonstrated that animals adapt to the predictability of a single stressor agent [12,57], in our study we used different stressors in a non-predicable way [49,50,63].…”

“…The stressing events were chosen randomly from the following procedures: forced restraint in a plastic tube for 2 h without access to food or water; forced bath in a cylindrical tank (0.60 m height x 0.30 m diameter) for 30 min in water at 32 • C; pairing with another stressed animal in wet sawdust (18 h); inversion of the light/dark cycle; crowded housing (8 rats living in a cage for 24 h); tail pinch for 10 min; hot air (approx. 38.00 • C) blown from a hair dryer for 10 min [48][49][50][51][52][53].…”

Mechanisms of initiation and reversal of drug-seeking behavior induced by prenatal exposure to glucocorticoids

“…Current views suggest that repetitive exposure to drugs of abuse evolve from goal-directed behaviors into habit-based actions (37,38). We previously demonstrated that stress, associated with increased GC secretion, alters the structure of the corticostriatal loops and steers the development of instrumental behavior into habitual behavior (39). The present demonstration of GCinduced programming of the structure and function of the NAcc provide, on the other hand, new insights into the mechanisms that underlie the transfer of conditioned 15 behavior to instrumental behavior.…”

Probabilistic inference under time pressure leads to a cortical-to-subcortical shift in decision evidence integration

“…Stress has been shown to bias decision-making strategies by reducing contributions of the prefrontal cortex (PFC) and encouraging habitual stimulus-response processes (Dias-Ferreira et al, 2009;Schwabe and Wolf, 2009). Specifically, learning the weather prediction task under stress induced by the cold pressor test has been associated with increased use of implicit, striatum-mediated strategies (Schwabe and Wolf, 2012).…”