Cortical Thickness and Folding Deficits in Conduct-Disordered Adolescents

Abstract

Background Studies of pediatric conduct disorder (CD) have described frontal and temporal lobe structural abnormalities that parallel findings in antisocial adults. The purpose of this study was to examine previously unexplored cortical thickness and folding as markers for brain abnormalities in “pure CD”-diagnosed adolescents. Based on current fronto-temporal theories, we hypothesized that CD youth would have thinner cortex or less cortical folding in temporal and frontal lobes than control subjects. Methods We obtained T1-weighted brain structure images from n=24 control and n=19 CD participants aged 12–18 years, matched by overall gender and age. We measured group differences in cortical thickness and local gyrification index (regional cortical folding measure) using surface-based morphometry with clusterwise correction for multiple comparisons. Results CD participants, when compared with controls, showed both reduced cortical thickness and folding. Thinner cortex was located primarily in posterior brain regions, including left superior temporal and parietal lobes, temporoparietal junction and paracentral lobule, right superior temporal and parietal lobes, temporoparietal junction and precuneus. Folding deficits were located mainly in anterior brain regions and included left insula, ventro- and dorsomedial prefrontal, anterior cingulate and orbitofrontal cortices, temporal lobe, right superior frontal and parietal lobes and paracentral lobule. Conclusions Our findings generally agree with previous CD volumetric studies, but here show the unique contributions of cortical thickness and folding to gray matter reductions in pure CD in different brain regions.

Cortical and Subcortical Abnormalities in Youths With Conduct Disorder and Elevated Callous-Unemotional Traits

“…With respect to structural MRI, several studies have reported reduced amygdala volume in this population (17-20) though two did not (21, 22) . Moreover, cortical volume (17,19,23) and thickness (24) are more generally reduced within temporal cortex in youth with CD. There have also been reports of insula abnormalities–either when indexed by volume, (18-20) cortical thickness (25) or folding (24) —though this is not always seen.…”

“…Moreover, cortical volume (17,19,23) and thickness (24) are more generally reduced within temporal cortex in youth with CD. There have also been reports of insula abnormalities–either when indexed by volume, (18-20) cortical thickness (25) or folding (24) —though this is not always seen. (21,22) Ventromedial prefrontal cortex reductions have also been reported—again either when indexed by volume, (17) cortical thickness (25) or folding (24) —though again this is not always seen (18-20,22) —one study reported increases in volume in this region.…”

“…There have also been reports of insula abnormalities–either when indexed by volume, (18-20) cortical thickness (25) or folding (24) —though this is not always seen. (21,22) Ventromedial prefrontal cortex reductions have also been reported—again either when indexed by volume, (17) cortical thickness (25) or folding (24) —though again this is not always seen (18-20,22) —one study reported increases in volume in this region. (21) Reduced caudate volume has been reported twice (19,20) but the absence of replications may only reflect a lack of investigations targeting this area.…”

“…With two very recent exceptions, (24,25) all published structural brain imaging studies of youth with CD have focused exclusively on indexing cortical gray matter volume. (17-22) This is problematic as cortical gray matter volume is a function of both cortical thickness and cortical surface area and these indices are increasingly viewed as separable endophenotypes for understanding the relationship of genetic influences on brain structure and function.…”

“…Moreover, there has been considerable heterogeneity in the cases investigated; ranging from patients with CD assessed by clinicians (19,24) to cases of CD as identified by computerized self-report (25) to individuals with extensive drug use. (22) In addition, groups have also not always been carefully matched for variables that are associated with individual differences in brain structure (e.g., IQ 24 ).…”