Max Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany.
J Neurosci. 2011 Jan 26;31(4):1246-53. doi: 10.1523/JNEUROSCI.2765-10.2011.
The close correlation between energy supply by blood vessels and energy consumption by cellular processes in the brain is the basis of blood flow-related functional imaging techniques. Regional differences in vascular density can be detected using high-resolution functional magnetic resonance imaging. Therefore, inhomogeneities in vascularization might help to identify anatomically distinct areas noninvasively in vivo. It was reported previously that cytochrome oxidase-rich blobs in the striate cortex of squirrel monkeys are characterized by a notably higher vascular density (42% higher than interblob regions). However, blobs have so far never been identified in vivo on the basis of their vascular density. Here, we analyzed blobs of the primary visual cortex of squirrel monkeys and macaques with respect to the relationship between vascularization and cytochrome oxidase activity. By double staining with cytochrome oxidase enzyme histochemistry to define the blobs and collagen type IV immunohistochemistry to quantify the blood vessels, a close correlation between oxidative metabolism and vascularization was confirmed and quantified in detail. The vascular length density in cytochrome oxidase blobs was on average 4.5% higher than in the interblob regions, a difference almost one order of magnitude smaller than previously reported. Thus, the vascular density that is closely associated with local average metabolic activity is a structural equivalent of cerebral metabolism and blood flow. However, the quantitative differences in vascularization between blob and interblob regions are small and below the detectability threshold of the noninvasive hemodynamic imaging methods of today.
血管提供的能量与脑细胞代谢消耗的能量之间的密切关联是血流相关功能成像技术的基础。利用高分辨率功能磁共振成像可以检测到血管密度的区域差异。因此，血管分布的不均匀性可能有助于在体内无创地识别解剖上不同的区域。先前有报道称，松鼠猴纹状皮层中富含细胞色素氧化酶的斑点区域的血管密度明显较高（比斑点间区域高 42%）。然而，迄今为止，斑点的血管密度从未在体内被识别过。在这里，我们分析了松鼠猴和猕猴初级视皮层的斑点，以研究血管化与细胞色素氧化酶活性之间的关系。通过用细胞色素氧化酶酶组织化学染色来定义斑点，并用 IV 型胶原免疫组织化学来定量血管，我们证实并详细量化了氧化代谢与血管化之间的密切相关性。在细胞色素氧化酶斑点中的血管长度密度平均比斑点间区域高 4.5%，这个差异几乎小一个数量级，低于先前报道的水平。因此，与局部平均代谢活性密切相关的血管密度是大脑代谢和血流的结构等价物。然而，斑点和斑点间区域之间的血管化的定量差异很小，低于当今非侵入性血液动力学成像方法的检测阈值。
