Sex and brain maturation underlie the attribution of incentive salience to conditioned stimuli in Wistar rats

This study examines differences in response patterns based on associative learning strategies, focusing on goal-tracker (GT) and sign-tracker (ST) profiles in rats. To explore whether maturational processes influence the expression of these phenotypes, Experiment 1 analyzed the distribution of ST and GT profiles across developmental stages (6- and 16-week-old rats). The results indicated a developmental effect on response patterns; younger rats exhibiting a higher prevalence of the GT profile, and no significant sex differences were observed. Experiment 2 assessed the ability of GT and ST animals to suppress their previously expressed behavioral patterns using an omission training procedure. Adult rats demonstrated greater response suppression than adolescent rats. Furthermore, GT profiles showed greater sensitivity to response omission than ST profiles, suggesting that these differences may be related to prefrontal cortex maturation. Sex differences emerged as a crucial factor in adult rats, with female GTs displaying more effective omission than female STs. This finding is particularly important because it may reflect behavioral phenotypes associated with psychiatric disorders, including substance abuse. Taken together, these results highlight how developmental stage and sex influence response profiles in rats, providing translational clinical relevance for understanding core symptoms in neuropsychiatric disorders.