Figure 3.

BOLD fMRI signals representing synaptic relay stations along the spinothalamic tract and dorsal column pathways. A, Schematic illustration describing part of the typical spinothalamic tracts (blue) with synaptic relay in the dorsal horn of the spinal cord (L4) and the dorsal column pathway (orange) with synapse in the gracile nucleus in medulla oblongata (bregma, −13.56 mm) [schematic brain sections from the atlas by Paxinos and Watson (2005)]. B, In response to the stimulation of the right hindlimb with 0.5 mA, fMRI reveals a BOLD signal in medulla oblongata, centered in the right gracile nucleus (arrow). Signals are also noted in the right cerebellum (arrowheads). C, fMRI of the lumbar spinal cord demonstrating a BOLD signal in the right dorsal horn during right hindlimb stimulation at 2 mA.