Poster B106, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
Influence of sex on genetic contributions to default mode network associations: a structural MRI study of monozygotic and dizygotic twin pairs
Matthew Jerram1, Elena Molokotos1, Amy Janes1,2; 1Suffolk University, 2McLean Imaging Center
Neuroimaging has demonstrated sex-based differences in brain structure and function, including the default mode network (DMN). The DMN is also highly heritable, both functionally and structurally. To date, no research has yet examined how this heritability is impacted by sex. In this study, we used structural MRI (sMRI) to investigate sex differences in cortical surface area (SA) measures in the DMN in a group of monozygotic (MZ) and dizygotic (DZ) twins. We hypothesized that SA would be differentially correlated between the MZ and DZ pairs and that the pattern of correlation would differ between male and female pairs. Data from the Human Connectome Project were used for this study, which included 3T sMRI data for MZ (n = 72, 52 female) and DZ (n = 60, 35 female) twin pairs, aged 21-35 years. Analysis used a standard pipeline in freesurfer and SA was extracted from regions known to be part of the DMN, including the precuneus, posterior cingulate, rostral anterior cingulate and medial orbitofrontal cortex. Total DMN (sum of regional SAs) and individual regions were analyzed. Pearson correlation was calculated for SA within MZ and DZ twin sets. To provide a measure of genetic influence, Fisher’s z transformation examined the MZ-DZ difference in correlation within sex. Results showed that MZ-DZ differences in correlation were significantly larger for women than for men, indicating a stronger genetic influence in DMN structure in women. These results illustrate the importance of considering sex differences when examining the heritability of brain endophenotypes.
Topic Area: NEUROANATOMY