| Summary: | 碩士 === 國立陽明大學 === 生物醫學影像暨放射科學系暨研究所 === 98 === Sex differences in corpus callosum (CC) is a subject of long debate but the results are contradictory . To eliminate the possible variables which affect CC size , we enroll 80 healthy volunteers (40 for each sex) with matched age , handedness and education and use novel probabilistic tractograhy based segmentation which is better in charactering of each CC channels constitution to get the individual unique parcellation pattern . Base on segmental result, we compare the global/subregional volume and DTI indexes as Fractional Anisotropy( FA), First EigenValue (FEV), Radial Diffusivity (RD) and mean diffusivity (MD) .
CC and lateralization have been considered closely related because of location and function of CC . We use asymmetry index (AI) to asses the relationship between CC and lateralization .In view of the impact of sex on cognitive , female may have lager CC size based on more advantageous in empathic tasks which need stronger connection in disperse neural regions . So we proposed that change of CC morphology may be basis of such sex differences in neuropsychology and use empathizing quotient (EQ) and systemizing quotient (SQ) scores to model the cognitive behavior of subjects to perform the correlation analysis both with macrostructure and microstructure in CC .
Results show that whole and occipital segmented CC volume are larger in male. Temporal segmented CC volume are larger in female whereas FEV in temporal CC part is higher in male. We find negative correlation in temporal-AI and positive correlation in occipital-AI to the each corresponding CC subregion . EQ is found to has positive correlation with temporal CC subvolume , FEV in temporal part and FEV in parietal part . And negative correlation is found between RD index in temporal CC subregion and EQ score . All the significant relation are observed only in women .
Our results show sex affect CC size no matter in macro- or micro-structure . And different lateralization / asymmetry and social cognition pattern between sexes result in distinct influence on CC morphology and underlying neural structure . This finding provide a direct evidence about sex difference in CC and also suggest the relation about CC in part is the structure supporting for sex difference in neuropsychology . And our study also propose the role of the CC change with the different transferred function .
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