Researchers have developed a new imaging strategy that allows them to see the small, ultrastructural changes in dendritic spines during structural plasticity. They have captured the best of both imaging modalities by refining and elaborating on an established imaging technique called correlative light and electron microscopy (CLEM).
Using 2-photon optical microscopy and glutamate uncaging, the research team first produced structural plasticity in single dendritic spines. After that, they froze the induced spine in time at one of three different time points, each reflecting one of the primary stages of structural plasticity.
The researchers cut brain tissue samples containing the stimulated spines into ultra-thin sections using a specialized device called ATUMtome. Consequently, they re-imaged the slices using the extreme resolving power of the Electron Microscope to reveal the ultrastructural details and reconstruct accurate pictures of the spine’s complex topography. The new imaging strategy synergizes the best of both optical and EM microscopies, allowing the researchers to study spine structural changes never before seen in nanoscale resolution.