Wu Tao, Zhang Jiarong, Hallett Mark, Feng Tao, Hou Yanan, Chan Piu
1 Department of Neurobiology, Key Laboratory on Neurodegenerative Disorders of Ministry of Education, Beijing Institute of Geriatrics, Xuanwu Hospital, Capital Medical University, Beijing, China 2 Beijing Key Laboratory on Parkinson's Disease, Parkinson Disease Centre of Beijing Institute for Brain Disorders, Beijing, China
1 Department of Neurobiology, Key Laboratory on Neurodegenerative Disorders of Ministry of Education, Beijing Institute of Geriatrics, Xuanwu Hospital, Capital Medical University, Beijing, China 2 Beijing Key Laboratory on Parkinson's Disease, Parkinson Disease Centre of Beijing Institute for Brain Disorders, Beijing, China.
Brain. 2016 Jan;139(Pt 1):144-60. doi: 10.1093/brain/awv319. Epub 2015 Nov 2.
Micrographia is a common symptom in Parkinson's disease, which manifests as either a consistent or progressive reduction in the size of handwriting or both. Neural correlates underlying micrographia remain unclear. We used functional magnetic resonance imaging to investigate micrographia-related neural activity and connectivity modulations. In addition, the effect of attention and dopaminergic administration on micrographia was examined. We found that consistent micrographia was associated with decreased activity and connectivity in the basal ganglia motor circuit; while progressive micrographia was related to the dysfunction of basal ganglia motor circuit together with disconnections between the rostral supplementary motor area, rostral cingulate motor area and cerebellum. Attention significantly improved both consistent and progressive micrographia, accompanied by recruitment of anterior putamen and dorsolateral prefrontal cortex. Levodopa improved consistent micrographia accompanied by increased activity and connectivity in the basal ganglia motor circuit, but had no effect on progressive micrographia. Our findings suggest that consistent micrographia is related to dysfunction of the basal ganglia motor circuit; while dysfunction of the basal ganglia motor circuit and disconnection between the rostral supplementary motor area, rostral cingulate motor area and cerebellum likely contributes to progressive micrographia. Attention improves both types of micrographia by recruiting additional brain networks. Levodopa improves consistent micrographia by restoring the function of the basal ganglia motor circuit, but does not improve progressive micrographia, probably because of failure to repair the disconnected networks.
小写症是帕金森病的常见症状，表现为笔迹大小持续或逐渐减小，或两者兼有。小写症背后的神经关联尚不清楚。我们使用功能磁共振成像来研究与小写症相关的神经活动和连接调制。此外，还研究了注意力和多巴胺能给药对小写症的影响。我们发现，持续性小写症与基底神经节运动回路的活动和连接减少有关；而进行性小写症与基底神经节运动回路功能障碍以及额补充运动区、额扣带回运动区和小脑之间的连接中断有关。注意力显著改善了持续性和进行性小写症，同时激活了壳核前部和背外侧前额叶皮层。左旋多巴改善了持续性小写症，同时基底神经节运动回路的活动和连接增加，但对进行性小写症没有影响。我们的研究结果表明，持续性小写症与基底神经节运动回路功能障碍有关；而基底神经节运动回路功能障碍以及额补充运动区、额扣带回运动区和小脑之间的连接中断可能导致进行性小写症。注意力通过激活额外的脑网络改善了两种类型的小写症。左旋多巴通过恢复基底神经节运动回路的功能改善了持续性小写症，但没有改善进行性小写症，可能是因为未能修复断开的网络。
