Investigation of hand preference and sex effects on telencephalon morphology via DTİ-based parcellation method

Objective: Cerebral hemispheres differ from each other. Some of these asymmetries are related to hand preference, language, complex motor skills, while others are related to less distinct cognitive functions. Certain cerebral anatomic asymmetries can be seen both macroscopically and histologically. In this study, we aimed to investigate the effects of hand preference and sex on the telencephalon morphology by comparing the diffusion parameters of corticospinal tract (TCS), posterior limb of internal capsule (CICP), superior longitidunal fasciculus (FLS) and uncinate fasciculus (FU) with parcellation method. Methods: The study included 108 subjects (54 right, 54 left hand preference) in the age range 18-28 years and gender distribution was equal in two groups. 'Edinburgh handedness inventory' test was applied to determine hand preference. The raw data from the MRI was processed using MRI Studio image processing programm. Fractional anisotropy (FA) and mean diffusivity (MD) averages of TCS, FU, CICP, and FLS were calculated for all subjects for both hemispheres. Differences among individual hemispheres and hand preference and sex were assessed. Results: In both TCS and CICP, high FA and low MD values were detected in the left hemisphere in all subjects. FU FA values were higher in right handed females than left handed; left handed males than right handed. There was no difference between hemispheres. Low MD values were detected in the left hemisphere, regardless of hand preference in only women. When FLS was evaluated, MD was higher, FA was lower in the right hemisphere, regardless of hand preference and sex. Conclusion: In our study, using DTG, the best in vivo method of examining white matter pathways, we compared diffusion parameters of some pathways. Until now, this comparison has not been done using the DTI parcellation method. Our findings are thought to contribute to literature in this regard. Key words: Diffusion tensor imaging, MRI Studio, fractional anisotropy, hand preference.