FIG 1. MR image and corresponding histologic sections from normal rat spinal cord. A, Schematic diagram of major ascending and descending tracts in the rat spinal cord overlaid on a b = 0 (T2-weighted) image of a rat spinal cord. Regions of interest were drawn in the following tracts: rubrospinal tract (RST), reticulospinal tract (ReST), vestibulospinal (VST), fasciculus gracilis (FG), fascisulus cuneatus (FC), and dorsal corticospinal tract (dCST). While the dorsal white matter tracts are homogeneous, the ventral and lateral tracts are mixed with other fibers from the STT-spinothalamic tract and dSCT-dorsal spinocerebellar tract. A significant difference between the human and rat spinal cord is the location of the corticospinal tract. In the human, the corticospinal tract is located in the lateral white matter, while in the rat it is located in the dorsal white matter.