Fukushima Kikuro, Ito Norie, Barnes Graham R, Onishi Sachiyo, Kobayashi Nobuyoshi, Takei Hidetoshi, Olley Peter M, Chiba Susumu, Inoue Kiyoharu, Warabi Tateo
Department of Neurology, Sapporo Yamanoue Hospital, Sapporo, Japan
Department of Neurology, Sapporo Yamanoue Hospital, Sapporo, Japan.
Physiol Rep. 2015 Mar;3(3). doi: 10.14814/phy2.12361.
While retinal image motion is the primary input for smooth-pursuit, its efficiency depends on cognitive processes including prediction. Reports are conflicting on impaired prediction during pursuit in Parkinson's disease. By separating two major components of prediction (image motion direction memory and movement preparation) using a memory-based pursuit task, and by comparing tracking eye movements with those during a simple ramp-pursuit task that did not require visual memory, we examined smooth-pursuit in 25 patients with Parkinson's disease and compared the results with 14 age-matched controls. In the memory-based pursuit task, cue 1 indicated visual motion direction, whereas cue 2 instructed the subjects to prepare to pursue or not to pursue. Based on the cue-information memory, subjects were asked to pursue the correct spot from two oppositely moving spots or not to pursue. In 24/25 patients, the cue-information memory was normal, but movement preparation and execution were impaired. Specifically, unlike controls, most of the patients (18/24 = 75%) lacked initial pursuit during the memory task and started tracking the correct spot by saccades. Conversely, during simple ramp-pursuit, most patients (83%) exhibited initial pursuit. Popping-out of the correct spot motion during memory-based pursuit was ineffective for enhancing initial pursuit. The results were similar irrespective of levodopa/dopamine agonist medication. Our results indicate that the extra-retinal mechanisms of most patients are dysfunctional in initiating memory-based (not simple ramp) pursuit. A dysfunctional pursuit loop between frontal eye fields (FEF) and basal ganglia may contribute to the impairment of extra-retinal mechanisms, resulting in deficient pursuit commands from the FEF to brainstem.
虽然视网膜图像运动是平稳追踪的主要输入，但它的效率取决于包括预测在内的认知过程。关于帕金森病患者追踪过程中预测受损的报道相互矛盾。通过使用基于记忆的追踪任务分离预测的两个主要成分（图像运动方向记忆和运动准备），并将追踪眼动与不需要视觉记忆的简单斜坡追踪任务中的眼动进行比较，我们检查了25例帕金森病患者的平稳追踪，并将结果与14名年龄匹配的对照组进行了比较。在基于记忆的追踪任务中，线索1指示视觉运动方向，而线索2指示受试者准备追踪或不追踪。基于线索信息记忆，受试者被要求从两个相反方向移动的点中追踪正确的点或不追踪。在25例患者中的24例中，线索信息记忆正常，但运动准备和执行受损。具体而言，与对照组不同，大多数患者（18/24 = 75%）在记忆任务期间缺乏初始追踪，而是通过扫视开始追踪正确的点。相反，在简单斜坡追踪期间，大多数患者（83%）表现出初始追踪。在基于记忆的追踪过程中正确点运动的突然出现对于增强初始追踪无效。无论左旋多巴/多巴胺激动剂药物治疗如何，结果都是相似的。我们的结果表明，大多数患者的视网膜外机制在启动基于记忆的（而非简单斜坡）追踪时功能失调。额叶眼区（FEF）和基底神经节之间功能失调的追踪环路可能导致视网膜外机制受损，从而导致从FEF到脑干的追踪指令不足。
