Corticospinal tract location in internal capsule of human brain: diffusion tensor tractography and functional MRI study.

We attempted to elucidate the corticospinal tract location at the posterior limb of the internal capsule in the human brain. Ten healthy volunteers were recruited. Probabilistic mapping was performed using the functional MRI activation resulting from a hand motor task as region of interest 1 and the corticospinal tract area of the anterior pons as region of interest 2. The average location of the highest density point of the corticospinal tract was mid-posterior portion with the standard from the most medial point to the most posterior point of the lenticular nucleus. In conclusion, we demonstrated that the corticospinal tract for the hand descended through the posterior portion of the posterior limb at the mid-thalamic level.