Zabberoni S, Carlesimo G A, Peppe A, Caltagirone C, Costa A
Department of Psychology, Niccolò Cusano University, Rome, Italy.
IRCCS Fondazione Santa Lucia, Rome, Italy.
Parkinsons Dis. 2017;2017:2837685. doi: 10.1155/2017/2837685. Epub 2017 Jun 11.
It has been hypothesised that, in Parkinson's disease (PD), dopamine might modulate spreading activation of lexical-semantic representations. We aimed to investigate this hypothesis in individuals with PD without dementia by assessing word frequency and typicality in verbal fluency tasks. We predicted that the average values of both of these parameters would be lower in PD patients with respect to healthy controls (HC). We administered letter-cued and category-cued fluency tasks to early PD patients in two experimental conditions: the tasks were administered both after 12-18 hours of dopaminergic stimulation withdrawal ("OFF" condition) and after the first daily dose of dopaminergic therapy ("ON" condition). HC were also given the two tasks in two conditions with the same intersession delay as PD patients but without taking drugs. Results showed that in both OFF and ON treatment conditions PD patients did not differ from HC in word frequency or typicality. Moreover, in the PD group, no significant difference was found between the experimental conditions. Our results show that semantic spreading was not altered in the PD sample examined; this suggests that in early PD the functioning of the semantic system is relatively independent from the activity of dopamine brain networks.
据推测，在帕金森病（PD）中，多巴胺可能会调节词汇语义表征的扩散激活。我们旨在通过评估言语流畅性任务中的词频和典型性，对无痴呆的PD患者的这一推测进行研究。我们预测，相对于健康对照（HC），这两个参数的平均值在PD患者中会更低。我们在两种实验条件下，对早期PD患者进行了字母提示和类别提示的流畅性任务：任务分别在多巴胺能刺激撤除12 - 18小时后（“关”状态）和每日首次给予多巴胺能治疗后（“开”状态）进行。HC也在两种条件下进行这两项任务，与PD患者的组间间隔相同，但不服用药物。结果显示，在“关”和“开”治疗条件下，PD患者在词频或典型性方面与HC没有差异。此外，在PD组中，实验条件之间未发现显著差异。我们的结果表明，在所研究的PD样本中语义扩散未发生改变；这表明在早期PD中，语义系统的功能相对独立于多巴胺脑网络的活动。
