Fig. 1: Ensheathment profiles along the auditory system in normal and dysmyelinated models.
a Scheme illustrating the auditory pathway with emphasis on the location of the inferior colliculus (IC) and auditory cortex (ACx). b Electron microscopy images of the IC of a Wt mouse (left panel) showing sparse compact myelin, and an Mbpshi/shi mouse (right panel), lacking electro-dense compact myelin. c Electron microscopy images of the auditory cortex of Wt (left), Mbpshi/shi (middle), and Mbpneo/neo mouse (right). Properly ensheathed axons in the ACx are marked with yellow asterisks. Insets show details of the myelin sheath of axons (Ax) from the respective image. Mbpshi/shi axons (right) show lack of compact myelin, while Mbpneo/neo axons (middle) show thinner compact myelin than Wt. The inset plot (middle) shows the quantification of the number of ensheathed axons per area in Wt (black, n = 3) and Mbpneo/neo (orange, n = 4), (two-sided Wilcoxon rank-sum test, P = 0.73, t = 0.434). The bar graph show the mean of all animals quantified (10–15 images per mouse). d Auditory brainstem-response (ABR) potentials. Left: group mean traces of control (black, n = 11). Pooled together seven Mbp+/+ and four Mbpshi/+, see Supplementary Fig. S2E for significances, and Mbpshi/shi (red, n = 7) mice. Each one of the five peaks (I–V) can be attributed to activity at a different station along the auditory brainstem (see Supplementary Fig. S2Aii). Responses in Mbpshi/shi mice were delayed at all auditory stations. Wave II appears divided and merged with wave III. Right: group mean traces of control (black, n = 8) and Mbpneo/neo (orange, n = 8) mice. Responses in Mbpneo/neo mice were delayed at all auditory stations. Scale bars: 2.5 µm (b), 2 µm (c). Source data are provided as a Source Data file.
