Information about action outcomes differentially affects learning from self-determined versus imposed choices

The valence of new information influences learning rates in humans: good news tends to receive more weight than bad news. We investigated this learning bias in four experiments, by systematically manipulating the source of required action (free versus forced choices), outcome contingencies (low versus high reward) and motor requirements (go versus no-go choices). Analysis of model-estimated learning rates showed that the confirmation bias in learning rates was specific to free choices, but was independent of outcome contingencies. The bias was also unaffected by the motor requirements, thus suggesting that it operates in the representational space of decisions, rather than motoric actions. Finally, model simulations revealed that learning rates estimated from the choice-confirmation model had the effect of maximizing performance across low- and high-reward environments. We therefore suggest that choice-confirmation bias may be adaptive for efficient learning of action–outcome contingencies, above and beyond fostering person-level dispositions such as self-esteem

The impact of ventral oral graft bulbar urethroplasty on sexual life

Objective: To evaluate the pre- and postoperative aspects of sexual life (SL) in patients with bulbar urethral stricture who underwent ventral oral graft urethroplasty. Methods: Between 2009 and 2010, 52 men (mean age 36 years) were enrolled in our prospective study to ascertain sexual disorders before and after surgery. The validated Male Sexual Health Questionnaire-Long Form (MSHQ-LF) was completed pre- and postoperatively; the unvalidated but adapted Post-Urethroplasty Sexual Questionnaire (PUSQ) was completed postoperatively. Data were compared using the non parametric Wilcoxon test. Results: Before urethroplasty, most of the patients reported sexual disorders, in particular reduced ejaculatory stream (85%); many of them (35%) feared the risk of a postoperative worsening in the quality of SL. After urethroplasty, nobody reported a worsened erection, while most of the patients noticed a significant improvement in erection, ejaculation, relationship with their partner, sexual activity, and desire. Modifications in the scrotoperineal sensitivity were reported by 42% and 15% noticed esthetic changes without impact on SL. All patients reported an improvement in quality of life (QOL) and were satisfied with the outcome of urethroplasty. Conclusion: Urethral stricture disease may be responsible for sexual disorders that have a significant impact upon SL. Patients confessed a marked anxiety tackling urethroplasty and declared that one of their deepest fears regarded a potential further deterioration in the quality of SL. At short-term follow-up, the minimally invasive ventral graft urethroplasty does not cause sexual complications, apart from the post-ejaculation dribbling. On the contrary, this technique showed to restore SL in all its aspects

Valence-dependent influence of serotonin depletion on model-based choice strategy.

Human decision-making arises from both reflective and reflexive mechanisms, which underpin goal-directed and habitual behavioural control. Computationally, these two systems of behavioural control have been described by different learning algorithms, model-based and model-free learning, respectively. Here, we investigated the effect of diminished serotonin (5-hydroxytryptamine) neurotransmission using dietary tryptophan depletion (TD) in healthy volunteers on the performance of a two-stage decision-making task, which allows discrimination between model-free and model-based behavioural strategies. A novel version of the task was used, which not only examined choice balance for monetary reward but also for punishment (monetary loss). TD impaired goal-directed (model-based) behaviour in the reward condition, but promoted it under punishment. This effect on appetitive and aversive goal-directed behaviour is likely mediated by alteration of the average reward representation produced by TD, which is consistent with previous studies. Overall, the major implication of this study is that serotonin differentially affects goal-directed learning as a function of affective valence. These findings are relevant for a further understanding of psychiatric disorders associated with breakdown of goal-directed behavioural control such as obsessive-compulsive disorders or addictions.This research was funded by Wellcome Trust Grants awarded to VV (Intermediate WT Fellowship) and Programme Grant (089589/Z/09/Z) awarded to TWR, BJE, ACR, JWD and BJS. It was conducted at the Behavioural and Clinical Neuroscience Institute, which is supported by a joint award from the Medical Research Council and Wellcome Trust (G00001354). YW was supported by the Fyssen Foundation. SP is supported by Marie Curie Intra-European Fellowship (FP7-People-2012-IEF).This is the final version of the article. It first appeared from NPG via http://dx.doi.org/10.1038/mp.2015.4