Table 1.
Characteristics of chronic pain subjects.
Figure 1.
Brain regions in which T2-relaxation times (upper panel) or mean diffusivity values (lower panel) were significantly reduced in subjects with painful trigeminal neuropathy compared with pain-free, healthy controls.
Significant reductions are colour-coded according to t-value and overlaid onto axial, coronal and sagittal sections of an individual subject’s T1-weighted image set. Slice locations in Montreal Neurological Institute space are indicated at the lower left of each image. ACC: anterior cingulate cortex; ispi: ipsilateral to side of on-going pain; MD: mean diffusivity; mPFC: medial prefrontal cortex; S1: primary somatosensory cortex.
Figure 2.
Brain regions in which both T2-relaxation times and mean diffusivity values (MD) were significantly reduced in subjects with painful trigeminal neuropathy compared with pain-free, healthy controls.
Areas of significant reductions are shaded green and overlaid onto axial, coronal and sagittal sections of an individual subject’s T1-weighted image set. Slice locations in Montreal Neurological Institute space are indicated at the lower left of each image. ACC: anterior cingulate cortex; ispi: ipsilateral to side of on-going pain; mPFC: medial prefrontal cortex; S1: primary somatosensory cortex.
Figure 3.
Plots of T2 relaxation times, mean diffusivity, gray matter volume and cerebral blood flow in three brain regions: the medial prefrontal cortex, anterior cingulate cortex and mediodorsal thalamus.
Control subjects are shaded black and chronic pain subjects are shaded white. Note that although T2 relaxation times and mean diffusivity is reduced in all three regions, there are no significant changes in either gray matter volume or resting cerebral blood flow. Location of reductions in T2 relaxation times and mean diffusivity are shown to the left and indicated by an arrow. Note the thalamic reductions are located within the mediodorsal nucleus (MD). CL: centrolateral; IC: internal capsule; LP: lateral posterior; Pul: pulvinar; VA: ventral anterior; VL: ventral lateral.
Table 2.
T2 relaxation, mean diffusivity, grey matter volume and cerebral blood flow values within the contralateral medial prefrontal cortex (mPFC), anterior cingulate cortex (ACC), mediodorsal thalamus, ipsilateral posterior insula and contralateral primary somatosensory cortex (S1).
Figure 4.
Sagittal slice showing location from which proton spectroscopy was performed in the contralateral medial prefrontal cortex (mPFC) of subjects with chronic pain and pain-free controls.
The bar graph shows mean (±SEM) NAA/Cr values for chronic pain patients and healthy controls. To the right are two plots of novelty seeking against mPFC NAA/Cr and mPFC T2 relaxation times against mPFC NAA/Cr. Note that both novelty seeking and mPFC T2 relaxation times are significantly correlated to NAA/Cr within the mPFC. NAA: N-acetyl aspartate; Cr: creatine.
Figure 5.
Plots of T2 relaxation times against novelty seeking temperament in control subjects (black circles) and in chronic pain subjects (gray squares) within the medial prefrontal cortex, anterior cingulate cortex and mediodorsal thalamus.
Note that in chronic pain subjects, T2 relaxation times in the medial prefrontal and anterior cingulate cortices are significantly negatively correlated to novelty seeking. No such relationship was found in controls. *indicates significant difference in r values between controls and chronic pain subjects determined using Fisher r-to-z transformation.