Department of Psychology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
Horm Behav. 2020 Sep;125:104815. doi: 10.1016/j.yhbeh.2020.104815. Epub 2020 Jul 18.
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.
决策是许多物种日常适应的一个复杂过程。风险是决策的固有方面，它受到性腺激素的影响。睾酮和 17β-雌二醇可能调节决策并影响中脑边缘多巴胺通路。在这里，我们探讨了性别差异、性腺激素的作用以及多巴胺激动剂安非他命对基于风险的决策的影响。完整或去势（GDX）雄性和雌性大鼠进行了概率折扣任务。给予高和低剂量的丙酸睾酮（1.0 或 0.2mg）和苯甲酸 17β-雌二醇（0.3μg），以评估对基于风险的决策的急性影响。经过 3 天的洗脱期后，完整和 GDX 大鼠接受高或低（0.5 或 0.125mg/kg）剂量的安非他命，并在概率折扣任务中重新测试。在基线条件下，雄性在概率折扣中比雌性做出更多的风险选择，特别是在较低概率的区块，但 GDX 不影响风险选择。高剂量但不是低剂量的睾酮适度减少了 GDX 雄性大鼠的风险决策。相反，17β-雌二醇对风险选择没有显著影响，无论 GDX 状态如何，在雄性和雌性中都是如此。最后，较高剂量的安非他命增加了完整雄性和雌性大鼠的风险决策，但对 GDX 大鼠没有影响。这些发现表明基于风险的决策存在性别差异，雄性表现出对更大、不确定奖励的更强偏见。GDX 状态影响安非他命的作用，表明雄性和雌性之间基于风险的选择存在不同的多巴胺调节。
