Jones Catherine R G, Malone Tim J L, Dirnberger Georg, Edwards Mark, Jahanshahi Marjan
Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London, UK.
Brain Cogn. 2008 Oct;68(1):30-41. doi: 10.1016/j.bandc.2008.02.121. Epub 2008 Apr 18.
A pervasive hypothesis in the timing literature is that temporal processing in the milliseconds and seconds range engages the basal ganglia and is modulated by dopamine. This hypothesis was investigated by testing 12 patients with Parkinson's disease (PD), both 'on' and 'off' dopaminergic medication, and 20 healthy controls on three timing tasks. In a seconds range (30-120 s) time production task, patients tested 'on' medication showed a significantly different accuracy profile compared to controls and when tested 'off' medication. However, no group or on vs off medication differences in accuracy were found on a time reproduction task and a warned reaction time task requiring temporal processing within the 250-2000 ms range. Variability was measured using the coefficient of variation, with the performance of the patient group on the time reproduction task violating the scalar property, suggesting atypical temporal processing mechanisms. The data suggest that the integrity of the basal ganglia is necessary for 'typical' time production in the seconds range as well as for time reproduction at shorter intervals. Exploratory factor analysis suggested that the time production task uses neural mechanisms distinct from those used in the other two timing tasks. The dissociation of the effects of dopaminergic medication and nature of task on performance in PD raises interesting questions about the pharmacological mediation and task-specificity of deficits in temporal processing.
时间文献中一个普遍的假设是，毫秒和秒范围内的时间处理涉及基底神经节，并受多巴胺调节。通过对12名帕金森病（PD）患者进行测试来研究这一假设，这些患者在服用和未服用多巴胺能药物的情况下，以及20名健康对照者参与了三项时间任务。在一个秒级范围（30 - 120秒）的时间生成任务中，服用药物时接受测试的患者与对照组相比，以及与未服用药物时接受测试的情况相比，表现出显著不同的准确性特征。然而，在一个时间再现任务和一个需要在250 - 2000毫秒范围内进行时间处理的预警反应时间任务中，未发现组间或服药与否在准确性上的差异。使用变异系数来测量变异性，患者组在时间再现任务中的表现违反了标量特性，表明存在非典型的时间处理机制。数据表明，基底神经节的完整性对于秒级范围内的“典型”时间生成以及较短间隔的时间再现都是必要的。探索性因素分析表明，时间生成任务使用的神经机制与其他两项时间任务所使用的机制不同。多巴胺能药物的作用与任务性质对PD患者表现的分离，引发了关于时间处理缺陷的药理学介导和任务特异性的有趣问题。
