Fig. 8.

Oligodendrocyte cytoplasm protrusions into the main axon space seen after traumatic brain injury. Electron micrographs are from sections through the dorsal columns (A,C) and ventral columns (B, D) (C6–7 level). (A) Lobular evaginations of oligodendrocyte cytoplasm. These entities are separated from axons via intact membranes (arrowheads). Some axons have cytoskeletal disorganization (ax₁ in A;); compare with a normal axon without evident affiliation with such evaginations (ax₂ in A). (B) Cross-sectional configuration of evaginations similar to the ones in (A). (C) Some evaginations contain dark oligodendrocyte cytoplasm (arrowhead) and vacuolar or hyperdense inclusions (asterisk). (D) Axon showing evidence of evagination process. The inner tongue of the oligodendrocyte (oli; shown in orange), intends deeply the axon and partially partitions the axoplasm (Ax; light blue). Note the degenerative flocculation and absence of microtubules in the axoplasm. DC, dorsal column; VC, ventral column. Scale bars: 500 nm. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)