Purdue University, West Lafayette, IN 47907, USA.
Neuropsychologia. 2012 Jul;50(9):2290-302. doi: 10.1016/j.neuropsychologia.2012.05.033. Epub 2012 Jun 8.
Parkinson's disease (PD) is caused by the accelerated death of dopamine (DA) producing neurons. Numerous studies documenting cognitive deficits of PD patients have revealed impairments in a variety of tasks related to memory, learning, visuospatial skills, and attention. While there have been several studies documenting cognitive deficits of PD patients, very few computational models have been proposed. In this article, we use the COVIS model of category learning to simulate DA depletion and show that the model suffers from cognitive symptoms similar to those of human participants affected by PD. Specifically, DA depletion in COVIS produced deficits in rule-based categorization, non-linear information-integration categorization, probabilistic classification, rule maintenance, and rule switching. These were observed by simulating results from younger controls, older controls, PD patients, and severe PD patients in five well-known tasks. Differential performance among the different age groups and clinical populations was modeled simply by changing the amount of DA available in the model. This suggests that COVIS may not only be an adequate model of the simulated tasks and phenomena but also more generally of the role of DA in these tasks and phenomena.
帕金森病（PD）是由多巴胺（DA）产生神经元的加速死亡引起的。大量记录 PD 患者认知缺陷的研究揭示了他们在与记忆、学习、视空间技能和注意力相关的各种任务中存在缺陷。虽然有几项研究记录了 PD 患者的认知缺陷，但很少有计算模型被提出。在本文中，我们使用 COVIS 类别学习模型来模拟 DA 耗竭，并表明该模型患有与受 PD 影响的人类参与者相似的认知症状。具体来说，COVIS 中的 DA 耗竭导致基于规则的分类、非线性信息整合分类、概率分类、规则保持和规则转换出现缺陷。通过模拟年轻对照组、老年对照组、PD 患者和 5 项著名任务中严重 PD 患者的结果，观察到了这些缺陷。不同年龄组和临床人群之间的差异表现通过简单地改变模型中可用的 DA 量来建模。这表明 COVIS 可能不仅是模拟任务和现象的合适模型，而且更普遍地是 DA 在这些任务和现象中的作用的模型。
