Single molecule microscopy allows nanometer localization of the detected emitters and subtle probing of their spatio-temporal nano-environment including in living neuronal cells . I will present several single molecule strategies using different nano-emitters to probe complex and confined neuronal environments.
These include the development of a new probe delivery method in the live animal brain to perform the first single quantum dot tracking in acute brain slices  and an original strategy based on phase imaging aiming towards 3D single particle tracking and 3D super-resolution microscopy in thick cellular environments .
For deep tissue imaging, single walled carbon nanotubes, which bear optical resonances in the near infrared and nanoscale dimensions, are particularly promising . I will show that, long trajectories (>10 min) of nanotubes diffusing in the brain extracellular space can be recorded at the single nanotube level. Analysis their movements provides super-resolved maps of tissue structuration which can be modulated upon biochemical digestion of the brain extracellular matrix in live animals .