(a) In vivo staining of cortical myelin with
Fluoromyelin (FM) (red) labels only the reflective fibers (cyan). 10 μm
scale bar. (b) In vivo FM staining in the cortex
of a Thy1-YFP mouse showing that YFP-labeled axons (green), that are FM negative
and therefore unmyelinated axons (arrowhead), are not reflective. Dendrites
(arrow), which are never myelinated, are also not reflective. However, all FM
positive segments are reflective (cyan). 10 μm scale bar.
(c) Example of an axonal bifurcation in a Thy1-YFP mouse imaged
in vivo demonstrating that specific parts of an axon that
are FM positive are also reflective, however the unmyelinated, FM negative
portions of the same axon are not reflective (arrow). 3 μm scale bar.
(d) In vivo staining and imaging of myelin in
the sciatic nerve with FM (red), reveals the location of nodes of Ranvier
(arrows) which lack reflection (cyan). 15 μm scale bar (experiments were
replicated 3 times in n=13 mice).