TABLE 2. Regions showing significant gray matter increase or decrease after one month of daily morphine administration.
All listed regions demonstrated volume change that survived a height-level threshold corrected with the false discovery rate (FDR) of 0.01 (uncorrected p < 0.0005), and cluster threshold FDR of 0.05 (contiguous voxels > 49). (a) Regions showing a main effect change over time in the morphine group are listed first, followed by the MNI coordinates of the peak voxel, t-value of the peak voxel, the cluster FDR significance level, range of change with mean, and correlation with morphine dosage. Volume changes significantly associated with morphine dosage are in bold. Associations with morphine that met an additional FDR correction to control for the number of correlation tests (critical p = 0.015) have an additional asterisk. (b) All regions showing a main effect in the morphine group were then tested for a significant interaction effect with the placebo group (same height and cluster-level thresholds used). The interaction is first labeled as significant or non-significant, followed by the t-score and p-value of the interaction.
| Main effects (morphine group) |
Interaction (morphine versus placebo) |
|||||||
|---|---|---|---|---|---|---|---|---|
| Region | MNI Coordinates | t-value | FDR q | % change range (mean) |
rs (p) with dosage |
Significant? | t-score | p-value |
| Atrophy | ||||||||
| Bilateral rostral pons | −3, −22, −24 +5, −20, −24 |
9.00 8.62 |
<0.005 | 0.6 – 3.2% (2.2%) | −0.40 (0.309) | no | 3.41 | 0.00167 (n.s.) |
| R amygdala | +20, −5, −19 | 8.73 | <0.005 | 0.0 – 4.0% (2.4%) | 0.75 (0.012)* | yes | 5.58 | 0.00002 |
| L medial orbital gyrus | −14, +15, −16 | 7.33 | 0.010 | 0.9 – 3.7% (2.6%) | 0.25 (0.476) | yes | 4.68 | 0.00011 |
| R hippocampus | +26, −22, −21 | 6.34 | 0.040 | 0.3 – 2.8% (1.7%) | 0.60 (0.066) | no | 2.01 | 0.03028 (n.s.) |
| Hypertrophy | ||||||||
| L inferior frontal gyrus | −44, +15, 0 | 11.76 | 0.004 | 0.7 – 3.6% (2.5%) | 0.80 (0.006)* | no | 3.50 | 0.00137 (n.s.) |
| L dorsal posterior cingulate and BA 5 | −8, −43, +52 | 10.85 | 0.014 | 0.4 – 2.3% (1.5%) | 0.09 (0.802) | no | 2.62 | 0.00896 (n.s.) |
| R hypothalamus | +1, −4, −16 | 9.86 | 0.018 | 0.6 – 5.0% (3.1%) | 0.66 (0.037) | yes | 4.81 | 0.00008 |
| Bilateral mid cingulate | 0, +11, +24 | 9.68 | <0.005 | 0.9 – 4.9% (3.4%) | −0.29 (0.413) | yes | 4.98 | 0.00006 |
| L inferior frontal gyrus | −58, +11, +2 | 8.97 | <0.005 | 1.4 – 5.3% (3.5%) | 0.87 (0.001)* | yes | 4.75 | 0.00009 |
| R ventral posterior cingulate (BA 31) | +18, −31, +39 | 8.78 | 0.012 | 0.9 – 3.7% (2.6%) | 0.63 (0.050) | no | 3.38 | 0.00178 (n.s.) |
| L ventral posterior cingulate (BA 23) | −3, −30, +26 | 8.50 | 0.002 | 0.8 – 3.2% (2.1%) | 0.27 (0.444) | yes | 4.35 | 0.00020 |
| R caudal pons | +12, −30, −37 | 7.68 | <0.005 | 0.6 – 8.2% (4.1%) | 0.75 (0.012)* | yes | 5.77 | 0.00001 |
| L dorsal anterior cingulate (BA 32) | −1, +39, −3 | 7.16 | <0.005 | 0.7 – 5.0% (3.0%) | −0.32 (0.354) | yes | 4.83 | 0.00008 |