Corticosterone and decision-making in male Wistar rats: the effect of corticosterone application in the infralimbic and orbitofrontal cortex

Abstract

Corticosteroid hormones, released after stress, are known to influence neuronal activity and produce a wide range of effects upon the brain. They affect cognitive tasks including decision-making. Recently it was shown that systemic injections of corticosterone (CORT) disrupt reward-based decision-making in rats when tested in a rat model of the Iowa Gambling Task (rIGT), i.e., rats do not learn across trial blocks to avoid the long-term disadvantageous option. This effect was associated with a change in neuronal activity in prefrontal brain areas, i.e., the infralimbic (IL), lateral orbitofrontal (lOFC) and insular cortex, as assessed by changes in c-Fos expression. Here, we studied whether injections of CORT directly into the IL and lOFC lead to similar changes in decision-making. As in our earlier study, CORT was injected during the final 3 days of the behavioral paradigm, 25 min prior to behavioral testing. Infusions of vehicle into the IL led to a decreased number of visits to the disadvantageous arm across trial blocks, while infusion with CORT did not. Infusions into the lOFC did not lead to differences in the number of visits to the disadvantageous arm between vehicle treated and CORT treated rats. However, compared to vehicle treated rats of the IL group, performance of vehicle treated rats of the lOFC group was impaired, possibly due to cannulation/infusion-related damage of the lOFC affecting decision-making. Overall, these results show that infusions with CORT into the IL are sufficient to disrupt decision-making performance, pointing to a critical role of the IL in corticosteroid effects on reward-based decision-making. The data do not directly support that the same holds true for infusions into the lOFC.

Functional and Structural Remodeling of Glutamate Synapses in Prefrontal and Frontal Cortex Induced by Behavioral Stress

“…Chronic high-dose systemic injections of corticosterone were shown to cause significant reduction of spines in PFC pyramidal neurons of layer V and deficits in memory retention ( 67 ), and to induce a significant redistribution of apical dendrites in layers II/III, with an increase in the number of proximal dendrites and a reduction of distal dendrites ( 68 ). Repeated corticosterone injections within infralimbic and prelimbic medial PFC were also found to impair working memory and to improve memory consolidation, through a glucocorticoid receptor-dependent mechanism ( 69 ). On the other hand, repeated corticotropin-releasing factor infusion directly into the medial PFC increased general anxiety, but did not affect cue-conditioned fear 10 days post infusion ( 70 ).…”

Trait Anxiety Has Effect on Decision Making under Ambiguity but Not Decision Making under Risk

“…Unimpaired IGT performance has associated with intact function of the OFC [ 17 , 18 , 19 ]. Even in a rat analogue of the IGT, rats with OFC lesions preferred to choose larger but more unpredictable rewards over smaller but more reliable rewards under conditions of uncertainty and ambiguity [ 20 , 21 ] or showed inadapted behaviors and impaired performance [ 22 , 23 ]. However, previous studies have suggested that the dlPFC plays a major role in the GDT.…”

A test of stress, cues, and re-exposure to large wins as potential reinstaters of suboptimal decision making in rats

“…A number of new tasks for rats have been developed to study choice between options that vary in terms of economic costs and benefits. These include the rat Gambling Task (rGT; van den Bos et al, 2006 , 2012 , 2013 , 2014 ; Rivalan et al, 2009 , 2013 ; Zeeb et al, 2009 ; Zeeb and Winstanley, 2011 , 2013 ; Koot et al, 2012 , 2013 , 2014 ) and the probabilistic delivery task (PDT; Adriani and Laviola, 2006 ; Adriani et al, 2006 , 2009 , 2010 ; Koot et al, 2012 ; Zoratto et al, 2013 , 2014 ). On these tasks, contingencies are arranged so that choice of the large reward option(s) is economically suboptimal.…”