Enhanced Thalamic Functional Connectivity with No fMRI Responses to Affected Forelimb Stimulation in Stroke-Recovered Rats.
Enhanced Thalamic Functional Connectivity with No fMRI Responses to Affected Forelimb Stimulation in Stroke-Recovered Rats.
复制标题
增强的丘脑功能连接性，没有fMRI对中风恢复大鼠的前肢刺激的反应。
DOI：
10.3389/fncir.2016.00113
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发表时间：
2016
影响因子：
3.5
通讯作者：
Kim YR
中科院分区：
文献类型：
--
作者：
Shim WH;Suh JY;Kim JK;Jeong J;Kim YR
脑卒中后神经功能恢复已被广泛研究，以提供更好的理解神经生物学机制，治疗和患者管理。神经影像学技术的最新进展，特别是功能性磁共振成像（fMRI），已广泛有助于解开改变的神经功能和中风影响的脑区之间的关系。作为以前的调查结果，塑性重组和/或逐渐恢复的血流动力学功能磁共振成像反应的神经刺激已被建议为相关的机制中风恢复过程的基础。然而，不同的研究结果和模态依赖性的结果，模糊了变量的功能磁共振成像信号的正确解释。在这里，我们进行了诱发和静息状态功能磁共振成像（rs-fMRI），以澄清功能磁共振成像表型和中风后功能恢复之间的联系。这些实验的设计目的是使用单侧大面积中风的大鼠模型来检查病变对侧半球和其他未受损大脑区域内神经活动的改变，尽管受到严重损伤，但在中风后16个月几乎完全恢复。令人惊讶的是，这两个血氧水平依赖性和血液容积加权（CBVw）功能磁共振成像活动引起的电刺激中风影响的前肢是完全不存在的，未能揭示的神经起源的行为恢复。与此相反，功能连接图显示高度强大的rs-fMRI活动集中在对侧病变丘脑腹内侧核（VM）。使用流行的大鼠大脑中动脉模型进行的刺激诱导的fMRI研究中的阴性结果表明fMRI血流动力学反应与神经改善之间的弱相关性。结果强烈警告中风影响的fMRI信号的轻率解释，并证明rs-fMRI作为一种补充工具，有效地表征中风恢复。
Neurological recovery after stroke has been extensively investigated to provide better understanding of neurobiological mechanism, therapy, and patient management. Recent advances in neuroimaging techniques, particularly functional MRI (fMRI), have widely contributed to unravel the relationship between the altered neural function and stroke-affected brain areas. As results of previous investigations, the plastic reorganization and/or gradual restoration of the hemodynamic fMRI responses to neural stimuli have been suggested as relevant mechanisms underlying the stroke recovery process. However, divergent study results and modality-dependent outcomes have clouded the proper interpretation of variable fMRI signals. Here, we performed both evoked and resting state fMRI (rs-fMRI) to clarify the link between the fMRI phenotypes and post-stroke functional recovery. The experiments were designed to examine the altered neural activity within the contra-lesional hemisphere and other undamaged brain regions using rat models with large unilateral stroke, which despite the severe injury, exhibited nearly full recovery at ∼6 months after stroke. Surprisingly, both blood oxygenation level-dependent and blood volume-weighted (CBVw) fMRI activities elicited by electrical stimulation of the stroke-affected forelimb were completely absent, failing to reveal the neural origin of the behavioral recovery. In contrast, the functional connectivity maps showed highly robust rs-fMRI activity concentrated in the contra-lesional ventromedial nucleus of thalamus (VM). The negative finding in the stimuli-induced fMRI study using the popular rat middle cerebral artery model denotes weak association between the fMRI hemodynamic responses and neurological improvement. The results strongly caution the indiscreet interpretation of stroke-affected fMRI signals and demonstrate rs-fMRI as a complementary tool for efficiently characterizing stroke recovery.