Fig 5. Fiber-tracking results from a healthy control (A) with the entire cross-section of the spinal cord in both the superior (blue fibers) and inferior section (red fibers) used as seeding regions. Few tracks extend from end to end of the scan volume (covering slightly more than 2 vertebral bodies). Color coding the same fibers in accordance with local orientation of the first eigenvector (blue, rostral-caudal; red, left-right; green, anteroposterior), many of the fibers appear to converge on an emerging nerve root, suggesting that fiber crossing may be present. Restricting seeding to the lateral white matter in the in the most superior section (C) shows no penetration of these tracks into the central regions of the cord.