Table 2.
Relation between free water-corrected mean diffusivity and free water values of meso-cortical and meso-limbic pathways and cognitive function, apathy and gait performances
| VTA-dlPFC | VTA-mOFC | VTA-vlPFC | VTA-ACC | VTA-NAc | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| β (SE) | P-corrected | β (SE) | P-corrected | β (SE) | P-corrected | β (SE) | P-corrected | β (SE) | P-corrected | |
| Models for free water-corrected mean diffusivity | ||||||||||
| Processing speed | −0.02 (0.06) | 1.000 | −0.04 (0.08) | 1.000 | −0.14 (0.07) | 0.342 | −0.10 (0.08) | 1.000 | −0.05 (0.06) | 1.000 |
| Executive function | −0.02 (0.06) | 1.000 | −0.03 (0.07) | 1.000 | −0.03 (0.08) | 1.000 | 0.00 (0.07) | 1.000 | −0.04 (0.07) | 1.000 |
| Memory | 0.05 (0.06) | 1.000 | −0.04 (0.06) | 1.000 | −0.03 (0.06) | 1.000 | −0.06 (0.07) | 1.000 | −0.05 (0.05) | 1.000 |
| AES-score | −0.09 (0.06) | 0.833 | 0.00 (0.07) | 1.000 | 0.05 (0.06) | 1.000 | 0.17 (0.11) | 0.774 | 0.14 (0.07) | 0.305 |
| TUG-step | −0.13 (0.06) | 0.225 | −0.15 (0.07) | 0.197 | −0.05 (0.08) | 1.000 | 0.02 (0.06) | 1.000 | 0.10 (0.06) | 0.422 |
| TUG-time | −0.08 (0.06) | 1.000 | −0.03 (0.05) | 1.000 | −0.01 (0.06) | 1.000 | −0.01 (0.06) | 1.000 | 0.03 (0.06) | 1.000 |
| Models for free water | ||||||||||
| Processing speed | −0.15 (0.07) | 0.140 | −0.25 (0.10) | 0.070 | −0.31 (0.10) | 0.016 | −0.39 (0.11) | 0.003 | −0.13 (0.06) | 0.291 |
| Executive function | −0.11 (0.07) | 0.629 | −0.33 (0.10) | 0.011 | −0.42 (0.11) | 0.001 | −0.32 (0.10) | 0.010 | −0.16 (0.08) | 0.234 |
| Memory | −0.19 (0.07) | 0.028 | −0.29 (0.10) | 0.028 | −0.42 (0.10) | <0.001 | −0.46 (0.10) | <0.001 | −0.10 (0.06) | 0.787 |
| AES-score | 0.24 (0.07) | 0.005 | 0.16 (0.09) | 0.361 | 0.19 (0.10) | 0.327 | 0.23 (0.10) | 0.180 | −0.07 (0.12) | 1.000 |
| TUG-step | 0.20 (0.07) | 0.036 | 0.10 (0.12) | 1.000 | 0.00 (0.11) | 1.000 | 0.00 (0.11) | 1.000 | −0.05 (0.06) | 1.000 |
| TUG-time | 0.14 (0.07) | 0.260 | 0.07 (0.08) | 1.000 | 0.10 (0.09) | 1.000 | 0.13 (0.08) | 0.739 | 0.03 (0.05) | 1.000 |
Meso-cortical pathways included the ventral tegmental area (VTA)-dorsolateral prefrontal cortex (dlPFC), VTA-medial orbitofrontal cortex (mOFC), VTA-ventral lateral PFC (vlPFC) and VTA–anterior cingulate cortex (ACC) tracts; the meso-limbic pathway is referred to as the VTA-nucleus accumbens (NAc) tract. All models were adjusted for age, sex, education years, modified Centre for Epidemiologic Studies Depression Scale (CESD) score, the corresponding diffusion measures of white matter reference regions, small vessel disease (SVD) MRI markers and normalized brain volumes. β-Values are reported as the standardized β-values and standard error (SE). P-values were corrected for multiple comparisons (n = 6) using the Bonferroni method; P-corrected values in bold represent < 0.05. AES = Apathy Evaluation Scale; TUG = Timed Up and Go test.