Nelson Spruston and Jayaram Chandrashekar, two neuroscientists at the Howard Hughes Medical Institute (HHMI) Janelia Research Campus in Ashburn (Virginia), compiled this astonishing 3D map that tracks down the route of 302 (to date) neurons inside the mouse brain. The list should reach 1000 neurons by next year.
The 3D map can be browsed in real time, but the software has to load the neurons from the database; it takes some time but the result is absolutely worth. The software also allows the user to filter brain regions, or to visualize whole neurons, somata or axons.
Link to HHMI website
Link to MouseLight Neuron browser