  Deficient myelination of the brain is associated with neurodevelopmental
delays, particularly in high-risk infants, such as those born small in relation
to their gestational age (SGA). New methods are needed to further study this
condition. Here, we employ Color Spatial Light Interference Microscopy (cSLIM),
which uses a brightfield objective and RGB camera to generate pathlength-maps
with nanoscale sensitivity in conjunction with a regular brightfield image.
Using tissue sections stained with Luxol Fast Blue, the myelin structures were
segmented from a brightfield image. Using a binary mask, those portions were
quantitatively analyzed in the corresponding phase maps. We first used the
CLARITY method to remove tissue lipids and validate the sensitivity of cSLIM to
lipid content. We then applied cSLIM to brain histology slices. These specimens
are from a previous MRI study, which demonstrated that appropriate for
gestational age (AGA) piglets have increased internal capsule myelination (ICM)
compared to small for gestational age (SGA) piglets and that a hydrolyzed fat
diet improved ICM in both. The identity of samples was blinded until after
statistical analyses.
