Emergence of the Wallerian degeneration pathway as a mechanism of secondary brain injury

<正>Augustus Volney Waller was a renowned British neurophysiologist who birthed the axon degeneration field in 1850 by describing curdling and fragmentation of the glossopharyngeal and hypoglossal cranial nerves of a frog following a transection injury. The degeneration of axons after a transection injury is now known as Wallerian degeneration （WD）. Waller’s work was expanded by Santiago Ramón y Cajal who described in detail the morphological stages of WD from monitory fragmentation of the axon and the granular disintegration of the neurofibrils to the final resorption of the axon. Interest in this field burgeoned in the early 1990’s with the fortuitous discovery of a mutant mouse, known as the Wallerian degeneration Slow （WldS） mouse.