Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan.
Mol Med. 2021 Apr 15;27(1):40. doi: 10.1186/s10020-021-00301-7.
Evidence from dopaminergic image and cerebral blood flow/metabolism images have shed light on symptomatology of cognitive aspects in brain physiology of healthy human as well as patients with Parkinson's disease. Cognitive impairment in Parkinson's disease is characterized by executive, visuospatial, attentional disturbances. Dopaminergic system includes triadic parallel pathways. The mesostriatal pathway consist of posterolateral putamen and motor areas, the mesocortical pathway of dorsal caudate nucleus and dorsolateral prefrontal cortex, and the mesolimbic pathway of ventral striatum, anterior cingulate cortex. The mesocortical pathway is responsible for the executive function which may change by administration of dopaminergic medication. The mesolimbic pathway is associated with motivation and reward prediction which may result in depression or apathy when dopamine level was suboptimal, impulse control disorder and punding when dopamine was over the optimal level. Abnormal brain metabolism/perfusion related to cognitive impairment in Parkinson's disease are relatively reduced activity located in frontal and parietal association areas and relatively increased activity in the cerebellum. In the anterior brain, the mesocortical pathway, is responsible for verbal memory and executive function, which originates with caudate dopaminergic system and account for mild cognitive impairment of Parkinson's disease. The posterior brain system which includes the parietal, temporal, and occipital cortices, is responsible for the memory and visuospatial function, and related to cholinergic dysfunction and possibly glucocerebrosidase gene variants, relating to dementia in Parkinson's disease. The role of cerebellum in Parkinson's disease remains unclear but emerging evidence suggests that it may relate to the sequencing detection and affective symptoms. The dual syndrome hypothesis is helpful for understanding the mechanism of cognitive impairment in Parkinson's disease and optimal symptom management.
多巴胺能图像和脑血流/代谢图像的证据揭示了健康人类和帕金森病患者大脑生理学中认知方面的症状。帕金森病的认知障碍表现为执行、视空间、注意力障碍。多巴胺能系统包括三重复合途径。中脑纹状体途径包括后外侧苍白球和运动区，中脑皮质途径包括背侧尾状核和背外侧前额叶皮质，中脑边缘途径包括腹侧纹状体、前扣带皮质。中脑皮质途径负责执行功能，多巴胺能药物的给药可能会改变其功能。中脑边缘途径与动机和奖励预测有关，当多巴胺水平不足时可能导致抑郁或冷漠，当多巴胺水平过高时可能导致冲动控制障碍和强迫行为。与帕金森病认知障碍相关的异常脑代谢/灌注表现为额叶和顶叶联合区相对活动减少，小脑相对活动增加。在前脑，中脑皮质途径负责言语记忆和执行功能，起源于尾状核多巴胺系统，与帕金森病的轻度认知障碍有关。包括顶叶、颞叶和枕叶皮质在内的后脑系统负责记忆和视空间功能，与胆碱能功能障碍和可能的葡萄糖脑苷脂酶基因突变有关，与帕金森病痴呆有关。小脑在帕金森病中的作用尚不清楚，但新出现的证据表明，它可能与序列检测和情感症状有关。双重综合征假说有助于理解帕金森病认知障碍的机制和最佳症状管理。
