Regulation of Central Nervous System Myelination in Higher Brain Functions

Figure 1

Myelin formation in the hippocampus of humans at different developmental stages. (a) At the 37th gestational week (GW), MBP-positive myelin segments (brown) are present in the fimbria (F), in the entire alveus (A), and in the stratum lacunosum-moleculare (L-M) of the CA1 region. MBP-positive OL cell bodies (arrowheads) and myelin segments (arrows) are present in the fimbria fornicis (b), in the alveus (c), and in the stratum lacunosum-moleculare (L-M) (d) in an infant born at the 37th GW. (e) At 2 years of age, strong MBP staining was observed in the alveus, in the stratum lacunosum-moleculare (L-M) of Ammon’s horn, and in the outer half of the molecular layer (M) of the dentate gyrus. MBP-positive myelin segments are also present in the strata oriens (O), pyramidale (P), and radiatum (R) of Ammon’s horn. (f) MBP-positive myelin segments in the hilus (H) of dentate gyrus at 2 years of age. (g) MBP-positive myelin segments start to form a dense network in the hilus of the dentate gyrus at the age of 11 years. (h) Much denser network of myelin segments in the hilus of a 53-year-old adult. Scale bars: 1000 μm in (e), 500 μm in (a), 250 μm in (g) and (h), and 100 μm in (b)–(d) and (f). This figure is modified from Abrahám et al. [31], with copyright permission for reusing the figure panels.

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