Background

Work in humans has shown that impulsivity can be advantageous in certain settings. However, evidence for so-called functional impulsivity is lacking in experimental animals.

Aims

This study investigated the contexts in which high impulsive (HI) rats show an advantage in performance compared with mid- (MI) and low impulsive (LI) rats. We also assessed the effects of dopaminergic and noradrenergic agents to investigate underlying neurotransmitter mechanisms.

Methods

We tested rats on a variable inter-trial interval (ITI) version of the 5-choice serial reaction time task (5CSRTT). Rats received systemic injections of methylphenidate (MPH, 1 mg/kg and 3 mg/kg), atomoxetine (ATO, 0.3 mg/kg and 1 mg/kg), amphetamine (AMPH, 0.2 mg/kg), the alpha-2a adrenoceptor antagonist atipamezole (ATI, 0.3 mg/kg) and the alpha-1 adrenoceptor agonist phenylephrine (PHEN, 1 mg/kg) prior to behavioural testing.

Results

Unlike LI rats, HI rats exhibited superior performance, earning more reinforcers, on short ITI trials, when the task required rapid responding. MPH, AMPH and ATI improved performance on short ITI trials and increased impulsivity in long ITI trials, recapitulating the behavioural profile of HI. In contrast, ATO and PHEN impaired performance on short ITI trials and decreased impulsivity, thus mimicking the behavioural profile of LI rats. The effects of ATO were greater on MI rats and LI rats.

Conclusions

These findings indicate that impulsivity can be advantageous when rapid focusing and actions are required, an effect that may depend on increased dopamine neurotransmission. Conversely, activation of the noradrenergic system, with ATO and PHEN, led to a general inhibition of responding.

中文翻译：

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5 选择系列反应时间任务中冲动性的适应性以及与儿茶酚胺能药物作用的相互作用：对 ADHD 的影响

 背景

对人类的研究表明，冲动在某些情况下可能是有利的。然而，实验动物中缺乏所谓功能性冲动的证据。

 目标

本研究调查了高冲动（HI）大鼠与中（MI）和低冲动（LI）大鼠相比表现出性能优势的背景。我们还评估了多巴胺能和去甲肾上腺素能药物的作用，以研究潜在的神经递质机制。

 方法

我们对大鼠进行了五项选择系列反应时间任务 (5CSRTT) 的可变试验间隔 (ITI) 版本的测试。大鼠接受全身注射哌醋甲酯（MPH，1 mg/kg 和 3 mg/kg）、托莫西汀（ATO，0.3 mg/kg 和 1 mg/kg）、安非他明（AMPH，0.2 mg/kg）、α-2a 肾上腺素受体在行为测试之前使用拮抗剂阿替美唑（ATI，0.3 mg/kg）和α-1肾上腺素受体激动剂去氧肾上腺素（PHEN，1 mg/kg）。

 结果

与 LI 大鼠不同，当任务需要快速反应时，HI 大鼠在短期 ITI 试验中表现出优异的表现，获得更多的强化物。 MPH、AMPH 和 ATI 提高了短期 ITI 试验中的表现，并增加了长期 ITI 试验中的冲动性，概括了 HI 的行为特征。相比之下，ATO 和 PHEN 会损害短期 ITI 试验的表现并降低冲动性，从而模仿 LI 大鼠的行为特征。 ATO对MI大鼠和LI大鼠的作用更大。

 结论

这些发现表明，当需要快速集中注意力和采取行动时，冲动可能是有利的，这种效果可能取决于多巴胺神经传递的增加。相反，ATO 和 PHEN 激活去甲肾上腺素能系统会导致反应的全面抑制。