Interpretation and validation of findings obtained on the basis of diffusion MRI relies on histological validation. An understanding of tissue characteristics can unveil the relationship between cellular substrates and tissue properties, and the MRI signal. Advances in light and electron microscopy provide new ways of imaging the brain tissue microstructure with high image resolution, with specific tissue contrast and in three dimensions, setting the stage for the development and implementation of advanced histological analyses for validating advanced diffusion MRI findings.