Three-dimensional tracking of axonal projections in the brain by magnetic resonance imaging

The relationship between brain structure and complex behavior is governed b y large-scale neurocognitive networks. The availability of a noninvasive te chnique that can visualize the neuronal projections connecting the function al centers should therefore provide new keys to the understanding of brain function. By using high-resolution three-dimensional diffusion magnetic res onance imaging and a newly designed tracking approach, we show that neurona l pathways in the rat brain can be probed in situ. The results are validate d through comparison with known anatomical locations of such fibers.