Table 3. Significant neuroimaging findings.
Brain Region | Coordinates (MNI) | Z Score | Finding | Cluster Size (mm3) | Significance (p value) |
---|---|---|---|---|---|
| |||||
Gray matter volume | |||||
PAG | 2,-31,-14 | 3.52 | HC > FM | 395 | .011† |
PAG connectivity negatively correlated with CPM (i.e. higher connectivity = more pain inhibition) | |||||
pgACC | 8,46,2 | 4.14 | HC & FM | 400 | .015† |
L Insula | -36,-6,-16 | 4.04 | HC & FM | 784 | .044* |
-46,2,-16 | 3.56 | ||||
DPons | 6,-32,-26 | 4.53 | HC Only | 736 | .007* |
6,-18,-20 | 3.66 | ||||
12,-22,-30 | 3.47 | ||||
CPons / RVM | -4,-28,-34 | 3.71 | HC > FM# | 584 | .009† |
-12,-20,-26 | 3.42 |
Note:
p<.05 familywise error corrected for multiple comparisons, derived from voxel-level threshold of p<.001;
p<.05 small volume corrected (See Table 4); PAG=periaqueductal gray; pgACC=perigenual anterior cingulate cortex; L=left; DPons=dorsal pons; CPons=caudal pons; RVM=rostral ventromedial medulla;
For this result, higher PAG connectivity was associated with more pain inhibition (i.e. correlation was more negative) in healthy subjects compared to a more facilitative effect of higher PAG connectivity on pain (i.e. correlation was more positive) in patients.