Jouzizadeh, Mojtaba2024-05-062024-05-062024-05-06http://hdl.handle.net/10393/46164https://doi.org/10.20381/ruor-30311Background: Understanding sex-specific differences in cognitive processes, such as mental rotation, is important for unraveling the complexities of human brain function and behavior. This study investigated putative sex differences in connectivity and signal variability during a 3D object mental rotation task using electroencephalography (EEG); these EEG-based indices have rarely been assessed in this context. -- Methods: Participants included 22 males and 20 females (18-41yr). Participants completed a mental rotation task during which they had to identify whether an object was the same but rotated or different. EEG-based connectivity was assessed using lagged coherence and complementary graph theory analytic methods were applied in assessing coherence [graph metrics: betweenness centrality (BC), clustering coefficient (CL), shortest path length (SPL), and small-world propensity (SWP). Signal variability was assessed using multiscale entropy (MSE). -- Results: Females exhibited lower accuracy than males on the task. Regarding coherence, in gamma band, males had greater coherence across multiple channels, in frontal and parietal regions; similar results were noted using regional analyses (greater within-region coherence in the gamma band was noted in the left prefrontal and parietal regions in males). Females, on the other hand, displayed greater theta band coherence in right central, prefrontal, and frontocentral regions. Males exhibited greater inter-hemispheric coherence between various regions than females in alpha and gamma bands. Complementary graph theory analyses indicated that, in alpha band, females demonstrated higher BC in left prefrontal region, while males exhibit higher BC in theta band in right parietal region. Notably, theta band CL was significantly greater in males within left prefrontal region whereas females display higher beta band CL in the right prefrontal region. Finally, females vs. males exhibited greater MSE values, particularly in frontal channels and regions, across all most bands (delta, theta, alpha, and gamma; fewest differences were noted in beta). -- Conclusion: Males tended to differ from females predominantly in the gamma band on coherence measures. This is notable given the involvement of gamma in cognition. Graph theory assessments yielded lateralization effects that were not evident with conventional methods. Increased MSE suggests greater variability in frontal regions in females, this might reflect greater frontal 'flexibility' that supports behaviour in females. In sum, this work advances our understanding of sex differences in one facet of cognitive processing, namely, mental rotation, and lays the groundwork for future investigations in this field.enAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Sex DifferencesEEGVisuospatialFunctional ConnectivityGraph Theory AnalysisSignal VariabilityThesis