Prefrontal cortex structural and developmental associations with callous-unemotional traits and aggression

Abstract

Youths with high levels of callous-unemotional (CU) traits and aggression are at an increased risk for developing antisocial behaviours into adulthood. In this population, neurostructural grey matter abnormalities have been observed in the prefrontal cortex. However, the directionality of these associations is inconsistent, prompting some to suggest they may vary across development. Although similar neurodevelopmental patterns have been observed for other disorders featuring emotional and behavioural dysregulation, few studies have tested this hypothesis for CU traits, and particularly not for aggression subtypes. The current study sought to examine grey matter correlates of CU traits and aggression (including its subtypes), and then determine whether these associations varied by age. Fifty-four youths (10-19 years old) who were characterized for CU traits and aggression underwent MRI. Grey matter volume and surface area within the anterior cingulate cortex was positively associated with CU traits. The correlation between CU traits and medial orbitofrontal cortex (mOFC) volume varied significantly as a function of age, as did the correlation between reactive aggression and mOFC surface area. These associations became more positive with age. There were no significant findings for proactive/total aggression. Results are interpreted considering the potential for delayed cortical maturation in youths with high CU traits/aggression.

Figure 1

Neurostructural correlates of CU traits. Neurostructural relationships between (a) ACC volume and CU traits, and (b) ACC surface area and CU traits. Morphometrics are expressed as a fraction of whole-brain values. CU callous-unemotional, ACC anterior cingulate cortex.

Figure 2

Age-specific neurostructural correlates of CU traits. Simple slopes analysis showing distinguishable associations between mOFC volume and CU traits at varying levels of the moderator variable age (1SD below mean age, mean age, 1SD above mean age). Morphometrics are expressed as a fraction of whole-brain values. CU callous-unemotional, mOFC medial orbitofrontal cortex.

Figure 3

Age-specific neurostructural correlates of reactive aggression. Simple slopes analysis showing distinguishable associations between mOFC surface area and reactive aggression at varying levels of the moderator variable age (1SD below mean age, mean age, 1SD above mean age). Morphometrics are expressed as a fraction of whole-brain values. CU callous-unemotional, mOFC medial orbitofrontal cortex.