Decision-making and frontoparietal resting-state functional connectivity among impulsive-compulsive diagnoses. Insights from a Bayesian approach.

The Iowa Gambling Task (IGT) is one of the most widely used paradigms for assessing decision-making. An impairment in this process may be linked to several psychopathological disorders, such as obsessive-compulsive disorder (OCD), substance abuse disorder (SUD) or attention-deficit/hyperactivity disorder (ADHD), which could make it a good candidate for being consider a transdiagnostic domain. Resting-state functional connectivity (rsFC) has been proposed as a promising biomarker of decision-making. In this study, we aimed to identify idiosyncratic decision-making profiles among healthy people and impulsive-compulsive spectrum patients during the IGT, and to investigate the role of frontoparietal network (FPN) rsFC as a possible biomarker of different decision-making patterns. Using functional near-infrared spectroscopy (fNIRS), rsFC of 114 adults (34 controls; 25 OCD; 41 SUD; 14 ADHD) was obtained. Then, they completed the IGT. Hybrid clustering methods based on individual deck choices yielded three decision-makers subgroups. Cluster 1 (n = 27) showed a long-term advantageous strategy. Cluster 2 (n = 25) presented a maladaptive decision-making strategy. Cluster 3 (n = 62) did not develop a preference for any deck during the task. Interestingly, the proportion of participants in each cluster was not different between diagnostic groups. A Bayesian general linear model showed no credible differences in the IGT performance between diagnostic groups nor credible evidence to support the role of FPN rsFC as a biomarker of decision-making under the IGT context. This study highlights the importance of exploring in depth the behavioral and neurophysiological variables that may drive decision-making in clinical and healthy populations.

Transcranial direct current stimulation improves risky decision making in women but not in men: A sham-controlled study.

Behavioral and anatomical sex-related differences have been traditionally found in decision-making processes assessed by Iowa Gambling Task (IGT). So far, the administration of transcranial direct current stimulation (tDCS) over orbitofrontal regions has shown an enhancing effect over decision-making. However, it is unknown whether there is a sex-dependent effect of stimulation in decision-making, a key question considering previous differences between men and women in IGT and the influence of individual differences in tDCS. The present study examines, at first time, the interaction between sex and tDCS in decision-making. For that aim, in a first experimental phase, ninety-two healthy participants performed the IGT. In a second phase, sixty-one participants received 20 min of anodal or sham tDCS over the right orbitofrontal cortex (rOFC) in a single-session pre-post sham-controlled study. To support the focality of the montage, a Stop Signal Task (SST) was used as a control task and also a numerical simulation of current flow distribution was performed. According to literature, in the first phase, results showed that men outperformed women in the IGT. In the second phase, the stimulation varied the IGT performance according to a sex specific manner: anodal tDCS increased the IGT performance in women, while in men; the stimulation did not produce any effect. Results were mediated by sex-specific morphological differences. These results highlight the necessity to consider the interaction of sex with the effect of the stimulation in future tDCS protocols, specifically in future clinical studies.

Behavioral and biological markers for predicting compulsive-like drinking in schedule-induced polydipsia.

Schedule-induced polydipsia (SIP), characterized by the development of persistent and excessive drinking under intermittent food-reinforcement schedules, is an animal model of compulsive behavior that can differentiate two populations: high drinkers (HD) and low drinkers (LD). The aim of the present study was to identify behavioral and biological markers to predict the vulnerability to developing compulsive-like drinking in SIP. Adult male Wistar rats were first trained in a spatial-discrimination serial reversal-learning task and in a reinforcer devaluation task to measure behavioral flexibility and habit formation, respectively. Subsequently, the rats were tested using the SIP protocol and identified as HD or LD based on their drinking rates. The performance of HD and LD rats in the two previous tasks was then analyzed. Before and after SIP exposure, blood glucose and plasma corticosterone (CORT) levels were measured. Additionally, serum electrolyte levels, including sodium, potassium, and chloride, were analyzed after SIP. HD rats showed higher behavioral inflexibility by exhibiting increased perseverative responses in the reversal-learning task and insensitivity to reinforcer devaluation during extinction under selective satiation. After SIP exposure, HD rats exhibited increased basal plasma CORT levels, indicating that this vulnerable group might have a dysregulation of the HPA axis. Although HD and LD rats had blood glucose levels within normal range, the HD group showed lower levels. The HD group did not exhibit hyponatremia (i.e., reduced serum sodium levels) when compared to LD rats after 20 daily SIP sessions. The results of the present study demonstrated that HD rats exhibit behavioral inflexibility and greater habitual-like behavior before SIP. Moreover, these results highlight the importance of measuring different behavioral and biological markers for predicting the vulnerability to developing compulsivity, and for enhancing the understanding of the pathophysiology of compulsive spectrum disorders.