Figure 1.

Illustration of the constitutive cellular elements of the neurovascular unit (NVU) along the entire brain vasculature. Panel (a) shows a panoramic view of the vascular tree. Panels (b–e) depict the different levels of the vascular tree. Pial arteries (panel (b)) run along the brain surface and penetrate the parenchyma, narrowing and branching into penetrating arterioles (panel (c)), which form the intraparenchymal arterioles (panel (d)), and ultimately give rise to capillaries (panel (e)). Abbreviations: IEL, internal elastic lamina; PVM, perivascular macrophage; SAS, the subarachnoid space; SMC, smooth muscle cell.