Figure 8.

Ultrastructural analysis of myelin in the human pre-mortem white matter. (A) Pre-embedding immunogold labeling shows that MBP is located in the outermost layer of the myelinated axon in the cerebral white matter of a 5-year-old female (PB19). (B) MAG is observed in the internal layer of the myelinated axon in direct contact with the axon in the white matter of a 5-year-old female (PB19). (C) Glutaraldehyde fixation allows a better analysis of the fine structure of myelin sheets in different stages of the myelination process, allowing to discern different myelin thickness. (D) Furthermore, it allows the visualization of the number of myelin layers. Ultrastructural analysis reveals that myelin is tightly packed, and exhibits variable periaxonal space. (C,D) Micrographs proceed from the white matter of a 2-year-old female (PB9) fixed with 2% PFA-2.5% Glutaraldehyde. mA, myelinated axon. Scale bars: 250 nm.