# Connectivity Alterations in Vascular Parkinsonism: A Structural Covariance Study
## 3 Results
### Structural Covariance Analysis
#### 3.1.2 Seed Region: Left Putamen  
The results of the structural covariance analysis from the Left Putamen (seed region) are reported in Table 3. Comparing the three groups (Figure 4), differences in structural associations between the Left Putamen and the rest of the brain were found in the Right Hippocamp (x: 21, y = \(-\)26, z: \(-\)9, \(p\) = 0.001 five cluster-level corrected) and in the Left Hippocamp (x: \(-\)12, y = \(-\)36, z: 3, \(p\) = 0.049 five cluster-level corrected). Compared to PD patients, VP patients showed fewer structural associations between the Left Putamen and the Left and Right Hippocamp (x: \(-\)12, y = \(-\)36, z: 3, \(p\) = 0.028 five cluster-level corrected, and x: 21, y = \(-\)26, z: \(-\)9, \(p\) = 0.05 five whole-brain corrected, respectively). Furthermore, when compared to HCs, VP patients displayed a reduced structural association between the Left Putamen and the Right Hippocamp (x: 27, y = \(-\)11, z: \(-\)11, \(p\) = 0.02 five whole-brain corrected), the Right Insula (x: 41, y = \(-\)11, z: 14, \(p\) < 0.001 five cluster-level corrected), the Left Rectus (x: \(-\)9, y = 23, z: \(-\)14, \(p\) = 0.016 five cluster-level corrected) and the Right Cerebellum Crus 2 (x: 17, y = \(-\)78, z: \(-\)36, \(p\) = 0.019 five cluster-level corrected). Nothing was found in the other post hoc comparisons (HCs more than PD, HCs less than PD, VP more than HCs and VP more than PD).  
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline \multicolumn{8}{c}{**ANOVA Comparisons among the Three Groups**} \\ \hline \multicolumn{8}{c}{_MNI Coordinates_} \\ \cline{2-8} _Brain Region_ & x & y & z & _F value_ & _Z-value_ & _p value_ & _Cluster extent_ \\ \hline Right Hippocamp & 21 & \(-\)26 & \(-\)9 & 16.98 & 4.34 & 0.001 ** & 1426 \\ Left Hippocamp & \(-\)12 & \(-\)36 & 3 & 15.81 & 4.21 & 0.049 ** & 590 \\ \hline \multicolumn{8}{c}{**Post hoc comparisons**} \\ \hline \multicolumn{8}{c}{_PND \textgreater{} VP_} \\ \hline \multicolumn{8}{c}{_MNI Coordinates_} \\ \cline{2-8} _Brain Region_ & \(x\) & \(y\) & \(z\) & _T value_ & _Z-value_ & _p value_ & _Cluster extent_ \\ \hline Left Hippocamp & \(-\)12 & \(-\)36 & 3 & 5.55 & 4.67 & 0.028 * & 4318 \\ Right Hippocamp & 21 & \(-\)26 & \(-\)9 & 5.50 & 4.64 & 0.05 * & \\ \hline \multicolumn{8}{c}{_HC \textgreater{} VP_} \\ \hline \multicolumn{8}{c}{_Brain Region_} \\ \cline{2-8} _Brain Region_ & x & y & z & _T value_ & _Z-value_ & _p value_ & _Cluster extent_ \\ \hline Right Hippocamp & 27 & \(-\)11 & \(-\)11 & 5.66 & 4.57 & 0.02 * & 2132 \\ \hline Right Insula & 41 & \(-\)11 & 14 & 4.95 & 4.28 & 0.001 ** & 1895 \\ \hline Left Rectus & \(-\)9 & 23 & \(-\)14 & 4.64 & 4.07 & 0.016 ** & 1102 \\ \hline Right Cerebellum Crus 2 & 17 & \(-\)78 & \(-\)36 & 3.97 & 3.58 & 0.019 ** & 1053 \\ \hline \hline \end{tabular}  
* * \(p\) < 0.05 five, whole-brain corrected. ** \(p\) < 0.05 five cluster level correction using an exploratory threshold of \(p\) < 0.001 uncorrected. Nothing was found for the other post hoc comparisons.  
\end{table}
Table 3: Structural covariance analysis. Seed region: Left Putamen.