Department of Neurology, Kiel University, Germany.
Department of Neurology, Kiel University, Germany.
Clin Neurophysiol. 2021 Dec;132(12):2937-2947. doi: 10.1016/j.clinph.2021.09.010. Epub 2021 Oct 11.
Planning of voluntary object-related movements requires the estimation of the most probable object properties. We investigated how 14 writer's cramp (WC) patients compared to 14 controls use probabilistic weight cues in a serial grip-lift task.
In every grip-lift trial, an object of either light, medium or heavy weight had to be grasped and lifted after a visual cue gave a probabilistic prediction of the object weights (e.g. 32.5% light, 67.5% medium, 0 % heavy). We determined peak (1) grip force GF, (2) load force LF, (3) grip force rate GFR, (4) load force rate LFR, while we registered brain activity with functional magnetic resonance imaging.
In both groups, GFR, LFR and GF increased when a higher probability of heavy weights was announced. When a higher probability of light weights was indicated, controls reduced GFR, LFR and GF, while WC patients did not downscale their forces. There were no inter-group differences in blood oxygenation level dependent activation.
WC patients could not utilize the decision range in motor planning and adjust their force in a probabilistic cued fine motor task.
The results support the pathophysiological model of a hyperfunctional dopamine dependent direct basal ganglia pathway in WC.
计划与物体相关的自愿运动需要估计最可能的物体属性。我们研究了 14 名书写痉挛（WC）患者与 14 名对照者在连续握持-提升任务中如何使用概率权重线索。
在每次握持-提升试验中，必须抓住一个轻、中或重的物体，然后在视觉线索给出物体重量的概率预测（例如 32.5%轻、67.5%中、0%重）后提起。我们确定了峰值（1）握持力 GF、（2）负载力 LF、（3）握持力速率 GFR、（4）负载力速率 LFR，同时我们使用功能磁共振成像记录大脑活动。
在两组中，当宣布重物的概率较高时，GFR、LFR 和 GF 增加。当指示轻重量的概率较高时，对照组降低了 GFR、LFR 和 GF，而 WC 患者则没有降低他们的力量。在血氧水平依赖激活方面没有组间差异。
WC 患者不能利用运动规划中的决策范围，并在概率提示的精细运动任务中调整其力量。
结果支持 WC 中多巴胺依赖性直接基底节通路功能亢进的病理生理模型。
