Quantitative Cerebrovascular Anatomy
Many contemporary functional brain imaging methods attempt to infer neural activity from the measurement of cerebral blood flow (CBF) or the concentration of blood borne substances, such as oxy-, and deoxyhemoglobin. In order to draw meaningful conclusions from such blood-based measurements, an understanding of the cerebral angioarchitecture is of great importance. Moreover, detailed knowledge of the 3D vascular topology is essential for realistic computational CBF modeling, spatially resolved brain energetics, and the understanding of onset and consequences of neurovascular diseases such as stroke. This project aims to quantify the vascular topology in 3D and to investigate the general organizational/topological principles that govern it.
Corrosion casts, immunohistochemistry, and cytochrome oxidase (COX) staining have been applied to quantify the vascular topology of the macaque visual cortex . Regional vascular length density, volume fraction, and surface density were computed and compared with the metabolic demand as measured by COX activity. The results suggest that the local degree of vascularization reflects the average metabolic activity.
Recent work involves the acquisition of high-resolution angiography data from rodent and monkey cerebral cortex, using synchrotron radiation based x-ray tomographic microscopy (SRXTM). The data need to be post-processed in order to improve signal to noise ratio, correct for sample deformation, and remove artificial vascular interrupts. Finally, the cerebral vasculature is represented in graph-format, which allows to study its topological properties, such as hierarchical organization, branching angles, segment length and diameter. The probability density function of these parameters can be studied across several cortical layers, which may provide insight about developmental principals of the cerebral microvascular network.
Hirsch S, Reichold J, Schneider M, Szekely G, Weber B.Topology and hemodynamics of the cortical cerebrovascular system. J Cereb Blood Flow Metab, 32(6):952-67, 2012.
 Keller AL, Schüz A, Logothetis NK and Weber B. The vascularization of cytochrome oxidase rich blobs in the primary visual cortex of primates. Journal of Neuroscience, 31(4):1246-53., 2011.
 Weber B, Keller AL, Reichold J,Logothetis NK. The Microvascular System of the Striate and Extrastriate Visual Cortex of the Macaque. Cereb Cortex. 18(10):2318-2330., 2008.
Swiss National Science Foundation
Max Planck Gesellschaft