# Sex-Related Variations in the Brain Motor-Network Connectivity at Rest during Puberty
## 3 Results  
### Differences of the Motor-Subnetwork in 12- and 16- Year-Old Male and Female Groups  
Figure 2 shows the comparison between male and female groups at age 12. Figure 2A is a representative coronal view of the MsN of a male and a female at age 12. The nodes in the motor regions were taken from the Power 264 region atlas. These network visualizations display the difference in the edge weight, which is related to the strength of the connections of a node. Figure 2B shows the PDF of the entire MsN, the arrows point to the corresponding comparison, in this case between the male and female group. Node strength values in the male group (solid line) span between 0 and 12, with strength values centered around 6. The female group showed more strength values between 10 and 12 than males, with most connections having a strength value around 5. The difference between the PDF of each sex at age 12 was greater in males than females (D = 0.141, \(p\)-value = 0.0001). At age 16, both groups had PDFs with values around 6, and the female group had male and female groups had no statistically significant difference (D = 0.078, \(p\)-value = 0.0779). Figure 2C shows the points of the individuals of the sample in the first and second components from the PCA analysis was carried out using the strength and leverage values; age and sex were considered categorical variables. The first component explains 19.4% of the variance, and the second is 7.8%. The male and female groups at age 12, which were found to have differences in the probability density comparison, correspond to the green and red dots, respectively. The female groups (red and blue) have the closest means. Visually, the male groups show distant means in this space. At age 12, the geometrical mean in the male group has higher negative values in the first component and almost zero in the second component, while at 16 the inverse is true, the mean has negative values in the second component and is zero in the first component. Females are both in the first quadrant at both ages. Top ten regions in the first component:  
Precentral.R2_Strength, Parietal_Inf.L1_Strength, Parcentral_Lobule.L1_Strength, Precentral.R3_Strength, Supp_Motor_Area.R2_Strength, Cingulum_Post.L1_Strength, Precuneus.R1_Strength, Supp_Motor_Area.R1_Strength, Postcentral.L4_Strength, Precuneus.L1_Strength  
Top ten regions in the second component:  
Figure 2: Sex and age differences in MsN of adolescents. (**A**) MsN coronal view of a representative male and female at ages 12 and 16. (**B**) The curves are the probability density function of the node strength for the MsN for males at age 12 (solid line) \(n\) = 22 and females at age 12 (dashed line) \(n\) = 28 (D = 0.141, \(p\)-value = 0). For males at age 16 (solid line) \(n\) = 20 and females at age 16 (dashed lines) \(n\) = 37 (D = 0.078, \(p\)-value = 0.044). Hand regions (30 blue spheres), mouth regions (5 green spheres) and cerebellar regions (4 red spheres). (**C**) Principal Component Analysis (PCA) using the strength and leverage values from the 39 regions. The colors as shown correspond to the 12- and 16-year-old female (F) and male (M) groups. The ellipses represent the confidence around the geometrical mean. Insua.R1_Strength, Postcentral.R7_Strength, Precentral.R4_Strength, Postcentral.L7_Strength Paracentral_Lobule.R1_Strength, Postcentral.L6_Strength, Precentral.R5_Strength Precentral.L2_Strength, Paracentral_Lobule.R1_Leverage, Postcentral.R6_Strength  
In conclusion, when the entire MsN was evaluated, there was a statistically significant difference in the node strength at age 12: the male group's node strength values are greater than those in the female group, while differences at age 16 are not significant. In the PCA analysis, 12-year-old females and males have visually different geometrical mean in the first and second component space. Female groups have a very similar geometrical mean, and 16-year-old males have almost orthogonal geometrical means, which suggests these populations undergo significant connectivity pattern changes.