Figure 1.

Degenerated axon profiles. The arrow on the left indicates an example of a degenerated axon profile that would be counted using criterion 1. A degenerated axon profile represents a late stage of axonal degeneration, during which debris from five to eight individual degenerated axons is surrounded by an intact myelin ring. The arrow on the right indicates a macrophage that has phagocytosed an axon and thus, stains positive for myelin. Criterion 2 includes both the degenerated axon profiles and macrophages in the degeneration counts. Bar, 10 μm.