Leunissen Inge, Coxon James P, Caeyenberghs Karen, Michiels Karla, Sunaert Stefan, Swinnen Stephan P
Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Belgium.
Movement Neuroscience Laboratory, University of Auckland, New Zealand.
Cortex. 2014 Feb;51:67-81. doi: 10.1016/j.cortex.2013.10.009. Epub 2013 Nov 4.
Traumatic brain injury (TBI) is associated with neuronal loss, diffuse axonal injury and executive dysfunction. Whereas executive dysfunction has traditionally been associated with prefrontal lesions, ample evidence suggests that those functions requiring behavioral flexibility critically depend on the interaction between frontal cortex, basal ganglia and thalamus. To test whether structural integrity of this fronto-striato-thalamic circuit can account for executive impairments in TBI we automatically segmented the thalamus, putamen and caudate of 25 patients and 21 healthy controls and obtained diffusion weighted images. We assessed components of executive function using the local-global task, which requires inhibition, updating and switching between actions. Shape analysis revealed localized atrophy of the limbic, executive and rostral-motor zones of the basal ganglia, whereas atrophy of the thalami was more global in TBI. This subcortical atrophy was related to white matter microstructural organization in TBI, suggesting that axonal injuries possibly contribute to subcortical volume loss. Global volume of the nuclei showed no clear relationship with task performance. However, the shape analysis revealed that participants with smaller volume of those subregions that have connections with the prefrontal cortex and rostral motor areas showed higher switch costs and mixing costs, and made more errors while switching. These results support the idea that flexible cognitive control over action depends on interactions within the fronto-striato-thalamic circuit.
创伤性脑损伤（TBI）与神经元丢失、弥漫性轴突损伤和执行功能障碍有关。传统上，执行功能障碍与前额叶病变相关，但大量证据表明，那些需要行为灵活性的功能严重依赖于额叶皮质、基底神经节和丘脑之间的相互作用。为了测试这种额-纹状体-丘脑回路的结构完整性是否可以解释TBI患者的执行功能受损情况，我们自动分割了25例患者和21名健康对照者的丘脑、壳核和尾状核，并获得了扩散加权图像。我们使用局部-全局任务评估执行功能的组成部分，该任务需要在动作之间进行抑制、更新和切换。形状分析显示基底神经节的边缘、执行和嘴侧运动区存在局部萎缩，而在TBI患者中丘脑萎缩更为普遍。这种皮质下萎缩与TBI患者的白质微观结构组织有关，表明轴突损伤可能导致皮质下体积减少。核团的总体积与任务表现没有明显关系。然而，形状分析显示，与前额叶皮质和嘴侧运动区有连接的那些子区域体积较小的参与者显示出更高的切换成本和混合成本，并且在切换时犯更多错误。这些结果支持这样一种观点，即对动作的灵活认知控制依赖于额-纹状体-丘脑回路内的相互作用。
