Sex differences in the human connectome: 4-Tesla high angular resolution diffusion imaging (HARDI) tractography in 234 young adult twins

• Published in: 2011 IEEE International Symposium on Biomedical Imaging: From Nano to Macro pp. 939 - 943
• Main Authors: Jahanshad, Neda, Aganj, Iman, Lenglet, Christophe, Joshi, Anand, Yan Jin, Barysheva, Marina, McMahon, Katie L, de Zubicaray, Greig I, Martin, Nicholas G, Wright, Margaret J, Toga, Arthur W, Sapiro, Guillermo, Thompson, Paul M
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.03.2011
• Subjects: Brain modeling; high angular resolution diffusion imaging (HARDI); human connectome; Humans; Image resolution; Imaging; inter-hemispheric connectivity; Joining processes; network analysis; Optical fiber networks; Optical fiber theory; tractography
• ISBN: 1424441277; 9781424441273
• ISSN: 1945-7928
• DOI: 10.1109/ISBI.2011.5872558

Cortical connectivity is associated with cognitive and behavioral traits that are thought to vary between sexes. Using high-angular resolution diffusion imaging at 4 Tesla, we scanned 234 young adult twins and siblings (mean age: 23.4 ± 2.0 SD years) with 94 diffusion-encoding directions. We applied a novel Hough transform method to extract fiber tracts throughout the entire brain, based on fields of constant solid angle orientation distribution functions (ODFs). Cortical surfaces were generated from each subject's 3D T1-weighted structural MRI scan, and tracts were aligned to the anatomy. Network analysis revealed the proportions of fibers interconnecting 5 key subregions of the frontal cortex, including connections between hemispheres. We found significant sex differences (147 women/87 men) in the proportions of fibers connecting contralateral superior frontal cortices. Interhemispheric connectivity was greater in women, in line with long-standing theories of hemispheric specialization. These findings may be relevant for ongoing studies of the human connectome.