Regulation of Central Nervous System Myelination in Higher Brain Functions

Figure 3

Mechanisms underlying activity-dependent regulation of myelination. (a) Diagram of the multiple steps involved in the development of OLs. OPCs differentiate into multipolar premyelinating OLs, which mature into myelinating OLs. Mature OLs form myelin segments on multiple axons simultaneously. Regulation can occur at different steps during development, eventually leading to altered myelin formation. (b) Nascent myelin sheaths are stabilized by activity-dependent secretion. Representative confocal images show the retraction of existing sheaths during 15 h time-lapse imaging in sibling control (left) and Tg(neurod1:TeNT-EGFP) larvae (right). In the right panel, expression of TeNT-EGFP disrupted axonal activity-dependent secretion. Images are lateral views of the dorsal spinal cord, and the time relative to the start of image acquisition is indicated for each image. For demonstrative purposes, sheaths stable for the entire time-lapse are shaded in blue. Retracting sheaths are shaded in red and are also indicated by red arrowheads (modified from Hines et al. [71], with copyright permission for reusing the figure panels). Scale bar: 5 μm.

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