Risk-based decision making in rats: Modulation by sex and amphetamine

• Published in: Hormones and behavior 2020-09, Vol.125, p.104815-104815, Article 104815
• Main Authors: Islas-Preciado, Dannia, Wainwright, Steven R., Sniegocki, Julia, Lieblich, Stephanie E., Yagi, Shunya, Floresco, Stan B., Galea, Liisa A.M.
• Format: Article
• Language: English
• Subjects: 17β-Estradiol; Amphetamine; Amphetamine - pharmacology; Animals; Behavior, Animal - drug effects; Behavior, Animal - physiology; Castration; Cognition; Cognition - drug effects; Cognition - physiology; Decision Making - drug effects; Decision Making - physiology; Decision-making; Delay Discounting - drug effects; Delay Discounting - physiology; Dopamine - pharmacology; Dopamine Agonists - pharmacology; Estradiol - analogs & derivatives; Estradiol - pharmacology; Female; Gonadal hormones; Male; Operant; Rats; Rats, Long-Evans; Reward; Risk Reduction Behavior; Sex Characteristics; Testosterone; Testosterone - pharmacology
• ISSN: 0018-506X; 1095-6867
• DOI: 10.1016/j.yhbeh.2020.104815

Decision-making is a complex process essential to daily adaptation in many species. Risk is an inherent aspect of decision-making and it is influenced by gonadal hormones. Testosterone and 17β-estradiol may modulate decision making and impact the mesocorticolimbic dopamine pathway. Here, we explored sex differences, the effect of gonadal hormones and the dopamine agonist amphetamine on risk-based decision making. Intact or gonadectomised (GDX) male and female rats underwent to a probabilistic discounting task. High and low doses of testosterone propionate (1.0 or 0.2 mg) and 17β-estradiol benzoate (0.3 μg) were administered to assess acute effects on risk-based decision making. After 3-days of washout period, intact and GDX rats received high or low (0.5 or 0.125 mg/kg) doses of amphetamine and re-tested in the probabilistic discounting task. Under baseline conditions, males made more risky choices during probability discounting compared to female rats, particularly in the lower probability blocks, but GDX did not influence risky choice. The high, but not the low dose, of testosterone modestly reduced risky decision making in GDX male rats. Conversely, 17β-estradiol had no significant effect on risky choice regardless of GDX status in either sex. Lastly, a higher dose of amphetamine increased risky decision making in both intact males and females, but had no effect in GDX rats. These findings demonstrated sex differences in risk-based decision making, with males showing a stronger bias toward larger, uncertain rewards. GDX status influenced the effects of amphetamine, suggesting different dopaminergic regulation in risk-based choices among males and females. •Male rats made more risky choices in the probability discounting task than females.•Gonadectomy (GDX) did not influence risk-based decision making in both sexes.•A high dose of amphetamine enhanced risky choices in intact male and female rats.•17β-estradiol did not affect risk-based decision making in male or female rats.