Three Planes of Human Brain: Coronal, Sagittal and Horizontal. White matter, in the dark-staining regions of these images, is responsible for the transmission of signals throughout the brain and is comprised largely of axon bundles. Ordinarily, these regions would be white in colour without staining. Grey matter, at the lighter edges of the slices, primarily consists of neuronal cell bodies, and contains all of the regions responsible for our higher bodily functions.
Image from study. Researchers say: "Getting guidance. Chemical cues help developing neurons make the right connections by telling them where to extend their branches, or axons. New structural studies of the interactions between one such cue and receptor molecules on the axons reveal how Netrin-1 molecules (blue and green) bind to two neogenin molecules (magenta and orange)."