Label-free and fluorescence imaging of oligodendrocytes and myelin.

Axonal myelination finely tunes action potential conduction to control precise timing in neural circuits. Little is known about how dynamic myelinating oligodendrocytes are in the adult brain primarily due to limited approaches for their investigation at the cellular level over time in their native environment. This protocol describes optical imaging approaches that allow specific label-free detection of compact myelin which, when combined with genetically encoded fluorescence reporters and small molecule dyes, permits high-resolution longitudinal and fixed sample imaging of myelin and oligodendrocytes in live mice, in live organotypic slices, and in postmortem tissues. Data generated with these approaches can be used to test fundamental questions related to myelin development, plasticity, maintenance, and repair.