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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冲动性的适应性方面以及与儿茶酚胺能药物在 5 选择系列反应时间任务中的作用的相互作用：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，在实验动物中缺乏所谓的功能冲动的证据。

目标

本研究调查了高脉冲 (HI) 大鼠与中 (MI) 和低脉冲 (LI) 大鼠相比表现出优势的环境。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

我们在 5 选择串行反应时间任务 (5CSRTT) 的可变试验间间隔 (ITI) 版本上测试了大鼠。大鼠接受哌醋甲酯（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 肾上腺素受体的全身注射在行为测试之前，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，HI 大鼠在短期 ITI 试验中表现出卓越的表现，获得更多的强化物，当任务需要快速响应时。MPH、AMPH 和 ATI 在短期 ITI 试验中提高了性能，并在长时间 ITI 试验中增加了冲动性，概括了 HI 的行为特征。相比之下，ATO 和 PHEN 在短暂的 ITI 试验中损害了表现并降低了冲动性，从而模仿了 LI 大鼠的行为特征。ATO对MI大鼠和LI大鼠的影响更大。

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，这种影响可能取决于增加的多巴胺神经传递。相反，使用 ATO 和 PHEN 激活去甲肾上腺素能系统导致普遍抑制反应。