Mei, F. et al. Nat. Med. 20, 954–960 (2014).

Fast axonal signaling is possible because of the insulating function of myelin, which is formed by oligodendrocyte membranes that wrap around axons. Mei et al. have developed a micropillar array that can be used to visualize myelination in high throughput. The conical pillars in the array serve as substrates for oligodendrocytes and thus allow the analysis of myelination even in the absence of neurons. Because of the conical shape of the pillars, concentric membrane layers can be visualized along the length of the pillars in a single image. These arrays are useful tools to study oligodendrocyte differentiation and myelin formation, and they can also be used to screen for compounds that affect the process of myelination.