Department of Psychology, University of Toronto, Toronto, ON, Canada.
Behav Brain Res. 2012 Apr 21;230(1):21-33. doi: 10.1016/j.bbr.2012.01.046. Epub 2012 Feb 1.
Although impulsive behavior is considered to peak during adolescence, relatively little empirical work has examined this issue. Sex differences in impulsivity across development are also poorly understood. We examined age and sex differences in impulsive action with a simplified version of the 5-choice serial reaction time test, using only 2 choices. Adolescent and adult male and female Sprague-Dawley rats were trained to respond to one of two possible brief light stimuli to receive a food reinforcer. Responding before the onset of the light stimulus (a premature response) was considered a measure of impulsive action. We also investigated age and sex differences in the impulsivity-inducing effects of drugs that (1) target neurotransmitter systems still developing during adolescence and (2) increase premature responding in adult rats. To this end, we examined the effects of increasing the inter-trial interval (ITI; 9s) and amphetamine (dopamine releaser; 0, 0.25, 0.5mg/kg; Experiment 1), Ro 63-1908 (glutamate NMDA receptor NR2B subunit antagonist; 0, 0.3, 1.0mg/kg; Experiment 2 & 3), and nicotine (nicotinic receptor agonist and indirect dopamine releaser; 0, 0.15, 0.3mg/kg; Experiment 3) on premature responding. Adolescent rats were more impulsive than adults. In response to a long ITI and amphetamine, adolescent males and adult females also made more premature responses compared to adult males. No consistent age or sex differences were observed for Ro 63-1908 or nicotine. These findings suggest that impulsive action is heightened in adolescents compared to adults. Further, age and sex differences in impulsive action may be mediated by dopamine.
虽然冲动行为被认为在青春期达到高峰，但相对较少的实证研究探讨了这个问题。在整个发展过程中，冲动行为在性别上的差异也知之甚少。我们使用仅包含两个选择的简化 5 选择连续反应时测试来检查冲动行为在年龄和性别上的差异，使用该测试来评估冲动行为。我们还研究了在冲动诱导药物的作用下，年龄和性别差异的情况，这些药物（1）针对的是在青春期仍在发育中的神经递质系统，（2）增加成年大鼠的提前反应。为此，我们研究了增加试验间间隔（ITI；9 秒）和安非他命（多巴胺释放剂；0、0.25、0.5mg/kg；实验 1）、Ro 63-1908（谷氨酸 NMDA 受体 NR2B 亚基拮抗剂；0、0.3、1.0mg/kg；实验 2 和 3）以及尼古丁（烟碱受体激动剂和间接多巴胺释放剂；0、0.15、0.3mg/kg；实验 3）对提前反应的影响。与成年人相比，青少年更冲动。在长 ITI 和安非他命的作用下，青少年男性和成年女性的提前反应也比成年男性多。对于 Ro 63-1908 或尼古丁，没有观察到一致的年龄或性别差异。这些发现表明，与成年人相比，青少年的冲动行为更为强烈。此外，冲动行为在年龄和性别上的差异可能是由多巴胺介导的。
