Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
Cereb Cortex. 2014 Feb;24(2):328-39. doi: 10.1093/cercor/bhs311. Epub 2012 Oct 25.
In this work, we show for the first time that the tangential diffusion component is orientationally coherent at the human cortical surface. Using diffusion magnetic resonance imaging (dMRI), we have succeeded in tracking intracortical fiber pathways running tangentially within the cortex. In contrast with histological methods, which reveal little regarding 3-dimensional organization in the human brain, dMRI delivers additional understanding of the layer dependence of the fiber orientation. A postmortem brain block was measured at very high angular and spatial resolution. The dMRI data had adequate resolution to allow analysis of the fiber orientation within 4 notional cortical laminae. We distinguished a lamina at the cortical surface where diffusion was tangential along the surface, a lamina below the surface where diffusion was mainly radial, an internal lamina covering the Stria of Gennari, where both strong radial and tangential diffusion could be observed, and a deep lamina near the white matter, which also showed mainly radial diffusion with a few tangential compartments. The measurement of the organization of the tangential diffusion component revealed a strong orientational coherence at the cortical surface.
在这项工作中，我们首次表明，在人类皮质表面，切向扩散分量具有方向一致性。我们使用扩散磁共振成像（dMRI）成功地追踪了在皮质内沿切向运行的皮质内纤维通路。与组织学方法相比，后者对人类大脑的三维结构几乎没有任何了解，dMRI 提供了对纤维方向的层依赖性的更多理解。对一个超高角度和空间分辨率的尸检脑组织块进行了测量。dMRI 数据具有足够的分辨率，可以在 4 个虚拟的皮质层内分析纤维方向。我们区分了一个位于皮质表面的层，其中扩散沿着表面是切向的；一个位于表面下方的层，其中扩散主要是径向的；一个覆盖 Gennari 纹的内层，其中可以观察到强烈的径向和切向扩散；以及一个靠近白质的深层，其中也主要显示径向扩散，只有少数切向隔室。切向扩散分量的组织测量揭示了皮质表面具有很强的方向一致性。
