## 4 Results and Discussion
### Discussion
A notable finding is the significant reduction in the number of features, indicating the effectiveness of the FS algorithms in identifying relevant features and eliminating unnecessary or redundant ones. Figure 13 shows the features selected by the GWO algorithm in the F6 group, which achieved the highest average accuracy. Some features consistently selected by multiple FS algorithms, emphasizing their importance and robustness. Supplementary Material Figure S2 provides a comprehensive overview of all selected features across different feature sets using the FS methods. Figure 12: Number of the selected features from the morphological sets using the different feature selection techniques. Then, to address the statistical question \"Does the mean MRI advantage differ between individuals with ASD and those without ASD\"?, we employed the independent t-test in IBM SPSS [61]. The figure encodes the results obtained from the analysis. Furthermore, in the Supplementary Material, Tables S6 and S7 provide detailed statistics, including mean, standard deviation, and mean standard error for the ASD and TD groups, as well as the results of the independent t-test for ABIDE subjects across all features. The performance results obtained in our study confirm the variability in the discriminatory power of individual morphometric feature sets. Notably, F5 and F6 consistently demonstrate the highest accuracy scores across most models in our experiments. F1 and F4 also exhibit occasional good performance, while F3 and F2 show relatively poor performance. These findings align with the conclusions of [PERSON] et al. [62], who stated that diagnostic models based on CT are preferable to volume-based models. Their study revealed specific changes in CT in various brain regions in children with ASD compared to controls. These regions include the left and right pars triangulars, left medial orbitofrontal gyrus, left parahippocampal gyrus, left frontal pole, left caudal anterior cingulate, and left precuneus. These regions are associated with social behavior regulation, social brain and mirror system hypothesis, cognitive regulation of behavior, and learning and repetitive behaviors [8; 14; 62]. However, our results highlight the importance of curvature in the F5 feature set and the use of multi-measurements in the F6 feature set. Previous research [63] confirmed noticeable cortical shape changes in children aged 7.5 to 12.5 years, supporting their relevance in ASD. The F1 feature set and volume measurements have shown classification potential. WM analysis is valuable for tracking abnormal congenital processes, particularly in cortico-cortical connections and neuronal migration [64]. Another study found increased CT in frontal lobe regions and reduced SA in the orbitofrontal cortex and posterior cingulum in ASD subjects compared to controls [65]. Our study replicated these findings. Moreover, we identified anomalies in CT and volume in the precentral region, impacting motor area stimulation along the precentral gyrus. The consistent agreement validates the reliability of these biomarkers. CatBoost, XGB, and SVM consistently achieved high performance with minimal variations in mean validation accuracy across our experiments. CatBoost generally had the highest accuracy, except in GWO-based experiments where SVM outperformed it, highlighting SVM's effectiveness with dimension-reduced medical data. On the other  
Figure 13: The selected features from the F6 sets using GWO-based feature selection techniques (GWO: Grey Wolf Optimization). Pink highlights indicate features consistently selected by multiple feature selection algorithms. hand, ensemble models offered stability and resilience, but CatBoost's interpretability was reduced due to its complexity [66]. NB performed poorly, possibly due to its assumption of equal feature significance. Including age and gender features improved GWO-SVM accuracy slightly to 71%, suggesting sample generalization can be influenced by age or gender distribution [66].