Decreased parallel diffusivity within the optic nerves of human patients after acute optic neuritis (55, 56) further corroborated the notion that decreased parallel diffusivity may be associated with various mechanisms of axonal damage, such as Wallerian degeneration, and diffuse axonal injury (57) that might have similarly occurred within the white matter of our MOG-IgG+ patients. Here, MOG is linked to optic neuritis.