The glial framework reveals white matter fiber architecture in human and primate brains

How to quantify local axonal orientations Mapping the axonal trajectories of the brain’s white matter at cellular resolution is a long-standing goal of neuroscience. However, existing methods for mapping the axons are either limited to animal studies or require highly specialized equipment for data acquisition and processing. Nissl staining identifies cell nuclei and has been used extensively to investigate parcellations of the cortical gray matter, but the white matter has largely been neglected with this technique. Schurr and Mezer now show that Nissl staining, together with structure tensor analysis, can be used to study white matter architecture and the organization of the glial cell framework around axons over the whole brain. This technique greatly advances our knowledge regarding the organization of glial cells and the fine-grained organization of axonal projections in the brain. —PRS