Figure 4

Nerves with severe degeneration often show preservation of nasal tracts of axons. (A, B) DiI-labeled optic nerves showing nasal tracts of staining. The left nerve only is shown for each mouse. The nerve in panel B is almost completely degenerated. The edge of the nerve sheath on the temporal side is marked with an arrow. Bar = 0.6 mm. (C) Silver-stained cross section of a nerve showing a peripheral tract of DiI-staining. This low resolution montage was made up of a series of photomicrographs taken at 1000X. The nasal part of the nerve is oriented to the right. Bar = 15 μm. (D-F) Higher resolution images of the respective boxed region in (C) shown above each panel. (D) Temporal optic nerve. (E) Central optic nerve. (F) Nasal optic nerve. The nasal region of this nerve contains a higher density of axons, consistent with the DiI-labeling pattern. Bar in (F) = 4 μm.