Substantia alba is a term used in neuroscience to describe the white matter of the brain, which comprises bundles of myelinated nerve fibers. Synonyms for this word include "white substance", "white matter", and "medullary substance". In Latin, "substantia" means substance or matter, while "alba" means white. The term substantia alba is used to differentiate the white matter from the gray matter of the brain, which contains unmyelinated nerve cell bodies. The white matter plays a critical role in the communication between different regions of the brain, allowing for the transmission of nerve impulses and coordination of various bodily functions.