Table 2. Regions Developing Nicotine Tachyphylaxis.
| Area (number of voxels) |
Group |
Group differences | |||
|---|---|---|---|---|---|
|
1 |
2 |
3 |
4 |
||
| Saline | 0.03 mg/kg | 0.10 mg/kg | 0.30 mg/kg | ||
| Primary cortex | |||||
| Auditory | −1.55±1.20a | 0.30±1.23 | 14.90±1.39 | 13.40±1.96 | 4a>4b |
| (158) | −2.44±1.10b | −1.97±1.30 | 7.37±3.44 | 1.45±3.10 | |
| Visual | −1.58±1.01 | −0.25±1.11 | 14.71±1.55 | 12.32±1.80 | 4a>4b |
| (125) | −1.56±1.18 | −1.74±1.00 | 7.39±3.26 | 2.22±3.16 | |
| Somatosensory | −1.61±0.85 | 0.48±1.06 | 13.20±1.15 | 12.81±1.25 | 3a>3b; 4a>4b |
| (1281) | −1.60±1.01 | −1.41±0.89 | 6.30±2.78 | 1.17±2.69 | |
| Insula | −1.63±0.96 | 0.72±1.21 | 16.85±1.69 | 14.65±1.34 | 4a>4b |
| (306) | −1.40±0.97 | −1.50±0.97 | 7.91±3.81 | 0.72±3.03 | |
| Motor | −1.23±0.90 | 0.73±1.07 | 15.35±1.94 | 11.26±1.12 | 3a>3b; 4a>4b |
| (431) | −0.66±1.00 | −1.01±0.71 | 7.26±3.12 | 0.35±2.72 | |
| Parietal | −1.49±1.03 | −0.18±1.01 | 14.23±1.49 | 11.59±1.58 | 3a>3b; 4a>4b |
| (143) | −1.49±1.05 | −1.66±0.87 | 6.96±2.98 | 1.71±2.95 | |
| Limbic cortex | |||||
| mPFC | −1.23±0.90 | 0.73±1.07 | 15.35±1.94 | 11.26±1.12 | 3a>3b; 4a>4b |
| (80) | −0.66±1.00 | −1.00±0.71 | 7.26±3.12 | 0.35±±2.72 | |
| Orbital | −1.88±0.67 | −0.27±1.24 | 13.70±1.15 | 8.62±1.55 | 3a>3b; 4a>4b |
| (124) | −0.03±0.91 | −1.45±0.75 | 6.00±2.54 | −0.94±2.89 | |
| Cingulate | −1.07±0.76 | 0.82±1.06 | 19.31±2.71 | 17.85±1.88 | 3a>3b; 4a>4b |
| (125) | −1.75±1.17 | −0.67±0.87 | 9.60±3.86 | 1.68±3.03 | |
| RSDG | −1.82±0.62 | 0.23±0.66 | 14.37±2.29 | 14.58±2.01 | 3a>3b; 4a>4b |
| (138) | −1.39±1.04 | −1.37±0.50 | 7.50±3.28 | 1.50±2.86 | |
| Perirhinal | −1.98±1.46 | −0.02±1.55 | 15.12±2.40 | 12.19±1.09 | 4a>4b |
| (22) | −2.68±0.85 | −2.14±1.95 | 7.15±4.22 | 0.88±3.08 | |
| Subcortical limbic system | |||||
| Hippocampus | −3.33±0.36 | −2.25±0.50 | 1.94±0.79 | −6.60±1.18 | 1b>1a; 4b>4a |
| (18) | −0.94±0.85 | −2.22±0.53 | −0.18±0.59 | −3.63±0.49 | |
| Caudate−putamen | −0.91±0.70 | 0.45±1.51 | 11.62±1.35 | 5.85±0.69 | 4a>4b |
| (68) | −2.47±1.06 | −1.94±1.09 | 5.71±3.59 | −1.05±1.90 | |
| Thalamus | −1.72±0.46 | 0.59±0.72 | 10.22±1.14 | 10.19±1.18 | 4a>4b |
| (210) | −1.41±1.23 | −1.18±0.80 | 5.28±2.49 | 2.23±1.99 | |
Abbreviations: mPFC, medial prefrontal cortex; RSDG, retrosplenial dysgranular and granular cortices.
The effects of sequential nicotine administration on the percentage change observed in peak CBV values relative to the baseline for each of the two injections. The upper and lower values represent the 1st and 2nd injections as shown by the exemplary superscripts a and b, respectively. Significant group differences were thresholded at p<0.05 after Bonferroni correction. Values represent the mean±SEM for each group.