Fig. 10.

Diffusion tensor imaging (DTI) reveals connections between brainstem structures and prefrontal cortex, both of which are known to be involved in descending control of pain. In particular, these data show putative connections between the nucleus cuneiformis (NCF) to ventromedial (vm) and dorsomedial (dm) prefrontal cortex (PFC). Diffusion-weighted EPI images were acquired with 60 diffusion gradient directions on a 1.5-T Siemens Sonata scanner, and are the average of three acquisitions. The processed images are in standard space and were constructed by binarizing the tracts for each subject and adding them together across the group (i.e. to create a frequency map). Voxel values represent the total number of subjects for which tracts pass through that given voxel. Data were processed with FMRIB's diffusion tools (http://www.fmrib.ox.ac.uk/fsl; see also Behrens et al. 2003).