Effective connectivity anomalies in human amblyopia
Effective connectivity anomalies in human amblyopia
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DOI：
10.1016/j.neuroimage.2010.07.053
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发表时间：
2011-01-01
期刊：
影响因子：
5.7
通讯作者：
Hess, Robert F.
中科院分区：
文献类型：
--
作者：
Li, Xingfeng;Mullen, Kathy T.;Hess, Robert F.
我们研究弱视患者外侧膝状体核和视皮层的有效连接。六名弱视患者参加了这项研究。标准视网膜定位刺激被用来定义早期视觉皮层区域的边界。我们获得了功能磁共振成像时间序列从丘脑，纹状体和纹外皮质区域的连接性研究。丘脑-纹状体和纹状体-纹状体外的网络构建的基础上已知的解剖连接和这些网络的有效连通性进行了评估，通过非线性系统识别方法。当由弱视眼驱动时，研究的所有网络的有效连接性都降低了，这表明与当前局部信号减少的单细胞模型相反，弱视缺陷的重要部分是由于不同大脑区域中细胞之间的异常相互作用。有效连接丢失与fMRI丢失无关，但与弱视程度（同侧LGN至V1连接）相关，这表明它可能是一种更相关的测量方法。前馈和反馈连接也受到类似的影响。一个半球的依赖性被发现的丘脑-纹状体前馈输入是不存在的反馈连接，这表明最近发现的弱视的人的LGN功能降低可能不仅仅是由皮质的反馈影响。腹侧和背侧的连接都减少了。(C)2010年爱思唯尔公司All rights reserved.
We investigate the effective connectivity in the lateral geniculate nucleus and visual cortex of humans with amblyopia. Six amblyopes participated in this study. Standard retinotopic mapping stimuli were used to define the boundaries of early visual cortical areas. We obtained fMRI time series from thalamic, striate and extrastriate cortical regions for the connectivity study. Thalamo-striate and striate-extrastriate networks were constructed based on known anatomical connections and the effective connectivities of these networks were assessed by means of a nonlinear system identification method. The effective connectivity of all networks studied was reduced when driven by the amblyopic eye, suggesting contrary to the current single-cell model of localized signal reduction, that a significant part of the amblyopic deficit is due to anomalous interactions between cells in disparate brain regions. The effective connectivity loss was unrelated to the fMRI loss but correlated with the degree of amblyopia (ipsilateral LGN to V1 connection), suggesting that it may be a more relevant measure. Feedforward and feedback connectivities were similarly affected. A hemispheric dependence was found for the thalamo-striate feedforward input that was not present for the feedback connection, suggesting that the reduced function of the LGN recently found in amblyopic humans may not be solely determined by the feedback influence from the cortex. Both ventral and dorsal connectivities were reduced. (C) 2010 Elsevier Inc. All rights reserved.