Ultra-high resolution in-vivo 7.0T structural imaging of the human hippocampus reveals the endfolial pathway.
Ultra-high resolution in-vivo 7.0T structural imaging of the human hippocampus reveals the endfolial pathway.
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人类海马体超高分辨率体内 7.0T 结构成像揭示了内叶通路。
DOI：
10.1016/j.neuroimage.2015.02.029
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发表时间：
2015
期刊：
影响因子：
5.7
通讯作者：
Zeineh,MichaelM
中科院分区：
文献类型：
--
作者：
Parekh,MansiB;Rutt,BrianK;Purcell,Ryan;Chen,Yuanxin;Zeineh,MichaelM
海马体是记忆形成和检索以及各种神经系统疾病（如阿尔茨海默病、癫痫和抑郁症）中非常重要的结构。它由许多复杂的亚区组成，这使得研究疾病期间发生的解剖变化变得困难。与猴子和啮齿类动物相比，人类的海马体海门可能具有独特的神经解剖结构，人类的CA3h区比啮齿类动物大得多，而且白质通路，称为叶内通路，可能只存在于人类。在本研究中，我们使用新开发的7.0 T全脑成像序列，平衡稳态自由进动（bSSFP），可获得0.4 mm各向同性图像，在体内研究海马门的解剖结构。根据解剖图谱对以下区域进行了详细的海马分区域分割：CA4、CA3、CA2、CA1、SRLM（狭缝辐射层分子）、肺泡、穹窿和枕下及其分子层。我们还分割了门内中心类似于叶内通路的低信号结构。为了验证这种低信号代表了叶内膜通路，我们在切除的标本上获得了0.1 mm各向同性8相周期bSSFP，然后用抗髓鞘碱性蛋白抗体（SMI 94）对标本进行了切片和髓鞘染色。在髓鞘染色切片上计算结构张量分析以显示下层纤维的方向性。所有受试者体内的海马体内的叶内通路一致可见。它是海马体中的一条中枢通路，与神经退行性疾病的相关性尚不清楚，但现在它可以无创地可视化，我们可以研究它在神经退行性疾病中的功能和改变。
The hippocampus is a very important structure in memory formation and retrieval, as well as in various neurological disorders such as Alzheimer's disease, epilepsy and depression. It is composed of many intricate subregions making it difficult to study the anatomical changes that take place during disease. The hippocampal hilus may have a unique neuroanatomy in humans compared to that in monkeys and rodents, with field CA3h greatly enlarged in humans compared to that in rodents, and a white-matter pathway, called the endfolial pathway, possibly only present in humans. In this study we have used newly developed 7.0 T whole brain imaging sequence, balanced steady-state free precession (bSSFP) that can achieve 0.4 mm isotropic images to study,in vivo, the anatomy of the hippocampal hilus. A detailed hippocampal subregional segmentation was performed according to anatomic atlases segmenting the following regions: CA4, CA3, CA2, CA1, SRLM (stratum radiatum lacunosum moleculare), alveus, fornix, and subiculum along with its molecular layer. We also segmented a hypointense structure centrally within the hilus that resembled the endfolial pathway. To validate that this hypointense signal represented the endfolial pathway, we acquired 0.1 mm isotropic 8-phase cycle bSSFP on an excised specimen, and then sectioned and stained the specimen for myelin using an anti-myelin basic protein antibody (SMI 94). A structure tensor analysis was calculated on the myelin-stained section to show directionality of the underlying fibers. The endfolial pathway was consistently visualized within the hippocampal bodyin vivoin all subjects. It is a central pathway in the hippocampus, with unknown relevance in neurodegenerative disorders, but now that it can be visualized noninvasively, we can study its function and alterations in neurodegeneration.