Yang Xue Q, Lauzon Brian, Seergobin Ken N, MacDonald Penny A
MacDonald Lab, Brain and Mind Institute, University of Western Ontario, London, ON, Canada.
Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.
Front Hum Neurosci. 2018 Jan 4;11:642. doi: 10.3389/fnhum.2017.00642. eCollection 2017.
Parkinson's disease (PD) is characterized by resting tremor, rigidity and bradykinesia. Dopaminergic medications such as L-dopa treat these motor symptoms, but can have complex effects on cognition. Impulse control is an essential cognitive function. Impulsivity is multifaceted in nature. Motor impulsivity involves the inability to withhold pre-potent, automatic, erroneous responses. In contrast, cognitive impulsivity refers to improper risk-reward assessment guiding behavior. Informed by our previous research, we anticipated that dopaminergic therapy would decrease motor impulsivity though it is well known to enhance cognitive impulsivity. We employed the Go/No-go paradigm to assess motor impulsivity in PD. Patients with PD were tested using a Go/No-go task on and off their normal dopaminergic medication. Participants completed cognitive, mood, and physiological measures. PD patients on medication had a significantly higher proportion of Go trial Timeouts (i.e., trials in which Go responses were not completed prior to a deadline of 750 ms) compared to off medication ( = 0.01). No significant ON-OFF differences were found for Go trial or No-go trial response times (RTs), or for number of No-go errors. We interpret that dopaminergic therapy induces a more conservative response set, reflected in Go trial Timeouts in PD patients. In this way, dopaminergic therapy motor impulsivity in PD patients. This is in contrast to the widely recognized effects of dopaminergic therapy on cognitive impulsivity leading in some patients to impulse control disorders. Understanding the nuanced effects of dopaminergic treatment in PD on cognitive functions such as impulse control will clarify therapeutic decisions.
帕金森病（PD）的特征是静止性震颤、僵硬和运动迟缓。左旋多巴等多巴胺能药物可治疗这些运动症状，但对认知可能有复杂影响。冲动控制是一项重要的认知功能。冲动性本质上是多方面的。运动冲动性是指无法抑制优势、自动、错误的反应。相比之下，认知冲动性是指指导行为的不当风险回报评估。基于我们之前的研究，我们预计多巴胺能治疗会降低运动冲动性，尽管众所周知它会增强认知冲动性。我们采用Go/No-go范式评估帕金森病患者的运动冲动性。帕金森病患者在服用和停用常规多巴胺能药物的情况下使用Go/No-go任务进行测试。参与者完成了认知、情绪和生理测量。与未服药相比，服药的帕金森病患者在Go试验中的超时比例（即Go反应在750毫秒截止时间前未完成的试验）显著更高（ = 0.01）。在Go试验或No-go试验的反应时间（RTs）以及No-go错误数量方面，未发现服药与未服药之间有显著差异。我们认为多巴胺能治疗会诱导更保守的反应模式，这在帕金森病患者的Go试验超时中得到体现。通过这种方式，多巴胺能治疗降低了帕金森病患者的运动冲动性。这与多巴胺能治疗对认知冲动性的广泛认可的影响形成对比，在一些患者中导致冲动控制障碍。了解多巴胺能治疗在帕金森病中对冲动控制等认知功能的细微影响将有助于明确治疗决策。
