In vivo retinotopic mapping of superior colliculus using manganese-enhanced magnetic resonance imaging
In vivo retinotopic mapping of superior colliculus using manganese-enhanced magnetic resonance imaging
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DOI：
10.1016/j.neuroimage.2010.07.015
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发表时间：
2011-01-01
期刊：
影响因子：
5.7
通讯作者：
Wu, Ed X.
中科院分区：
文献类型：
--
作者：
Chan, Kevin C.;Li, Jiang;Wu, Ed X.
上级丘（superior colliculus，SC）是哺乳动物中脑的一个圆顶状皮层下层状结构，其表层按拓扑学顺序接收来自视网膜的视觉信息。尽管越来越多的研究调查retinotopic投影在视觉脑发育和障碍，在体内，高分辨率的三维映射的地形组织在皮层下的视觉核团尚未提供。本研究探讨的能力，3D锰增强MRI（MEMRI）在200 μ m各向同性分辨率在体内视网膜定位映射的大鼠SC部分横断眶内视神经。双眼玻璃体内注射Mn 2+后1天，第1组（n = 8）中在右侧眶内上上级视神经处部分横断的动物在左侧SC的外侧区域与左侧内侧SC和右侧对照SC相比表现出显著较低的T1加权信号强度。7）导致左侧SC的吻侧或尾侧区域的T1加权低信号，而在所有组中观察到分离左侧SC的两半的清晰边界。以往的组织学和电生理学研究表明，视网膜神经节细胞轴突分别从视网膜的上级、下层、鼻侧和颞侧投射到对侧的外侧、内侧、尾侧和喙侧。啮齿类动物中的SC。虽然这种拓扑模式在眶内视神经中得以保留，但已表明部分横断上级眶内视神经主要导致上级而非下级视网膜和视神经的原发性损伤。这项研究的结果表明，亚毫米分辨率MEMRI的灵敏度在体内，3D映射的精确retinotopic预测SC后减少顺行轴突运输Mn2+离子从局部区域的前视觉通路的皮质下中脑核。未来的MEMRI研究设想在全球和纵向环境中测量大脑发育，疾病，可塑性和再生治疗的地形变化。(C)2010年爱思唯尔公司All rights reserved.
The superior colliculus (SC) is a dome-shaped subcortical laminar structure in the mammalian midbrain, whose superficial layers receive visual information from the retina in a topological order. Despite the increasing number of studies investigating retinotopic projection in visual brain development and disorders, in vivo, high-resolution 3D mapping of topographic organization in the subcortical visual nuclei has not yet been available. This study explores the capability of 3D manganese-enhanced MRI (MEMRI) at 200 mu m isotropic resolution for in vivo retinotopic mapping of the rat SC upon partial transection of the intraorbital optic nerve. One day after intravitreal Mn2+ injection into both eyes, animals with partial transection at the right superior intraorbital optic nerve in Group 1 (n = 8) exhibited a significantly lower T1-weighted signal intensity in the lateral region of the left SC compared to the left medial SC and right control SC. Partial transection toward the temporal or nasal region of the right intraorbital optic nerve in Group 2 (n = 7) led to T1-weighted hypointensity in the rostral or caudal region of the left SC, whereas a clear border was observed separating 2 halves of the left SC in all groups. Previous histological and electrophysiological studies showed that the retinal ganglion cell axons emanating from superior, inferior, nasal and temporal retina projected respectively to the contralateral lateral, medial, caudal and rostra! SC in rodents. While this topological pattern is preserved in the intraorbital optic nerve, it was shown that partial transection of the superior intraorbital optic nerve led to primary injury predominantly in the superior but not inferior retina and optic nerve. The results of this study demonstrated the sensitivity of submillimeter-resolution MEMRI for in vivo, 3D mapping of the precise retinotopic projections in SC upon reduced anterograde axonal transport of Mn2+ ions from localized regions of the anterior visual pathways to the subcortical midbrain nuclei. Future MEMRI studies are envisioned that measure the topographic changes in brain development, diseases, plasticity and regeneration therapies in a global and longitudinal setting. (C) 2010 Elsevier Inc. All rights reserved.