A simple biophysical model of an axon was used to study the catastrophic consequences of free radical damage to neurons. The result was that the axon collapsed into a deformed structure resembling a string of beads (right panel). This is the same morphology observed during the degeneration of actual neurons in the brain as seen in the center panel. Credit: Anat Hatzor and Paul Weiss, Penn State (right panel); Beth Leullen, Penn State (center and left panels).