Urban, N.T. et al. Biophys. J. 101, 1277–1284 (2011).

To study synapse function in a physiological setting, it is necessary to image deep in the brain. Urban et al. describe adaptation to a stimulated emission depletion (STED) super-resolution to facilitate actin imaging inside synapses 120 micrometers below the tissue surface. They equipped their STED microscope with a high-numerical-aperture glycerol-immersion objective lens with a correction collar, which greatly decreased aberrations resulting from light scattering.