Figure 5. Optical and mass spectrometry images of mouse optic nerve tissue. A: Optical image of mouse ocular tissue section coated with the 2,5-dihydroxybenzoic acid matrix. B: Matrix-assisted laser desorption ionization–imaging mass spectrometry (MALDI-IMS) image in negative ion mode at 10 µm spatial resolution of a mouse optic nerve illustrating the distribution and intensity of a deprotonated sphingolipid species C₄₈H₉₂NO₁₁S sulfatide (d18:1:24:0)) at m/z 890.6. C: MALDI-IMS image illustrating the distribution and intensity of a deprotonated sphingolipid species C₄₆H₈₈NO₁₂S (Sulfatide(d18:0/22:0(2OH)) at m/z 878.6.