The association between Callous-unemotional traits and disruptions in white matter connectivity
This research studies the relationship between severity of Conduct Disorder (CD) and microstructural integrity of white matter in young children. Severity of CD is behaviourally measured by the level of Callous-unemotional traits (CU). CU traits refer to symptoms of CD such as disregard for others, lack of empathy, and shallow affect. Diffusion Tensor Imaging scans (DTI) are used as a neurological measure of the microstructural integrity of white matter in the brain to quantify the overall directionality and movement of water molecules in each voxel of the brain. Fractional Anisotropy values (FA) are computed from the DTI scans. This metric reflects restrictiveness of diffusion on a scale from one to zero. This research focuses on the integrity of the Uncinate Fasciculus, a white matter tract that connects the amygdala and the orbitofrontal cortex. The amygdala regulates aggression and the orbitofrontal cortex is associated with decision making, thus the connectivity between these two regions is very relevant to CD. Three other pathways were also analyzed as controls in the hopes of demonstrating that the UF could independently predict severity of CU traits. The computed data from the DTI scans was entered in a linear regression model that controlled for IQ, gender, whole brain, movement, and ADHD severity. Results showed a strong association between high levels of CU traits and lower FA values. Future research will focus on other pathways in the hopes of proving that the UF has a unique effect on CU outcomes.