Background: Psychopathy is a personality disorder characterized by interpersonal and emotional abnormalities
(e.g., lack of empathy and guilt) and antisocial behavior. Psychopathy has been associated with a number of
structural brain abnormalities, most notably in orbital frontal and anterior/medial temporal regions, that may
underlie psychopathic individuals’ problematic behaviors. Past research evaluating cortical structure in psychopathy has considered thickness and volume, but to date no study has investigated differences in cortical
gyrification, a measure of cortical complexity thought to reflect early neurodevelopmental cortical connectivity.
Methods: We measured the local gyrification index (LGI) in a sample of 716 adult male inmates and performed a
whole brain analysis assessing the relationship between LGI and total and factor scores on the Hare Psychopathy
Checklist-Revised (PCL-R).

Results: PCL-R scores were negatively associated with LGI measures within the right hemisphere in the midcingulate cortex (MCC) and adjacent regions of the superior frontal gyrus as well as lateral superior parietal
cortex. Additionally, PCL-R Factor 1 scores (interpersonal/affective traits) predicted less LGI within the right
MCC and adjacent dorsomedial frontal cortex and greater LGI in bilateral occipital cortex. Scores on PCL-R
Factor 2, indicating impulsivity and antisocial behaviors, did not predict LGI in any regions.

Conclusions: These findings suggest that psychopathy, particularly the interpersonal and affective traits, are
associated with specific structural abnormalities that form during neurodevelopment and these abnormalities
may underlie aberrant brain functioning in regions important in emotional processing and cognitive control.