Laboratory of Neurology and Imaging of Cognition, Department of Fundamental Neurosciences, University of Geneva, Switzerland; Swiss Center for Affective Studies, University of Geneva, Switzerland; Department of Mental Health and Psychiatry, University Hospitals of Geneva, Switzerland; Geneva Neuroscience Center, University of Geneva, Switzerland.
Laboratory of Neurology and Imaging of Cognition, Department of Fundamental Neurosciences, University of Geneva, Switzerland.
Neuropsychologia. 2018 Jun;114:251-265. doi: 10.1016/j.neuropsychologia.2018.04.018. Epub 2018 Apr 23.
Motor conversion disorder (CD) entails genuine disturbances in the subjective experience of patients who maintain they are unable to perform a motor function, despite lack of apparent neurological damage. Abilities by which individuals assess their own capacities during performance in a task are called metacognitive, and distinctive impairment of such abilities is observed in several disorders of self-awareness such as blindsight and anosognosia. In CD, previous research has focused on the recruitment of motor and emotional brain systems, generally linking symptoms to altered limbic-motor interactions; however, metacognitive function has not been studied to our knowledge. Here we tested ten CD patients and ten age-gender matched controls during a visually-guided motor paradigm, previously employed in healthy controls (HC), allowing us to probe for motor awareness and metacognition. Participants had to draw straight trajectories towards a visual target while, unbeknownst to them, deviations were occasionally introduced in the reaching trajectory seen on the screen. Participants then reported both awareness of deviations and confidence in their response. Activity in premotor and cingulate cortex distinguished between conscious and unconscious movement corrections in controls better than patients. Critically, whereas controls engaged the left superior precuneus and middle temporal region during confidence judgments, CD patients recruited bilateral parahippocampal and amygdalo-hippocampal regions instead. These results reveal that distinct brain regions subserve metacognitive monitoring for HC and CD, pointing to different mechanisms and sources of information used to monitor and form confidence judgments of motor performance. While brain systems involved in sensory-motor integration and vision are more engaged in controls, CD patients may preferentially rely on memory and contextual associative processing, possibly accounting for how affect and memories can imbue current motor experience in these patients.
运动转换障碍（CD）涉及到患者的真实主观体验障碍，尽管他们没有明显的神经损伤，但他们仍然维持着无法执行运动功能的说法。个体在执行任务时评估自身能力的能力被称为元认知，而在几种自我意识障碍（如盲视和否认症）中，这种能力的明显损伤被观察到。在 CD 中，以前的研究主要集中在运动和情绪大脑系统的招募上，通常将症状与改变的边缘运动相互作用联系起来；然而，据我们所知，元认知功能尚未得到研究。在这里，我们在一项视觉引导的运动范式中测试了 10 名 CD 患者和 10 名年龄和性别匹配的对照组，该范式以前在健康对照组（HC）中使用，使我们能够探究运动意识和元认知。参与者必须朝着视觉目标画出直线轨迹，而在他们不知道的情况下，有时会在屏幕上看到的到达轨迹中引入偏差。然后，参与者报告对偏差的意识和对其反应的信心。在控制组中，与无意识运动校正相比，运动前皮质和扣带皮质的活动能更好地区分有意识和无意识运动校正。至关重要的是，在做出信心判断时，对照组会激活左侧上顶叶和中颞叶区域，而 CD 患者则会激活双侧海马旁回和杏仁核-海马区域。这些结果表明，不同的大脑区域为 HC 和 CD 提供了元认知监测，指出了用于监测和形成运动表现信心判断的不同机制和信息来源。虽然涉及感觉运动整合和视觉的大脑系统在对照组中更为活跃，但 CD 患者可能更倾向于依赖记忆和上下文联想处理，这可能解释了情感和记忆如何在这些患者中赋予当前运动体验。
