Luxol fast blue staining of myelin. Greater myelin density stains darker azure (blue). In piglet brain, the internal capsule consists of discontinuous white matter bundles with intervening parcels of gray matter. Thus, at anterior levels, the internal capsule in piglet is a heterogeneous white matter-gray matter structure. Myelin density was measured in the region of interest encompassing caudate (C), internal capsule (IC), and putamen (P). The external capsule (EC), left ventricle (LV), septum, and ventral pallidum (VP) are also identified.