Paracingulate Sulcus Asymmetry in the Human Brain: Effects of Sex, Handedness, and Race

Abstract

The anterior cingulate cortex (ACC), which is thought to play a key role in cognitive and affective regulation, has been widely reported to have a high degree of morphological inter-individual variability and asymmetry. An obvious difference is in the morphology of the paracingulate sulcus (PCS). Three types of PCS have been identified: prominent, present, and absent. In this study, we examined the relationship between PCS asymmetry and whether the asymmetry of the PCS is affected by sex, handedness, or race. PCS measurements were obtained from four datasets. The statistical results revealed that the PCS was more often prominent and present in the left hemisphere than in the right. The percentage of right-handed males with a prominent PCS was greater than that of right-handed females, but the percentage of left-handed males with a prominent PCS was lower than that of left-handed females. In addition, both male and female and both left-handed and right-handed subjects showed a leftward asymmetry of the PCS. Furthermore there were no significant racial differences in the leftward asymmetry of the PCS. Our findings about the morphological characteristics of the PCS may facilitate future clinical and cognitive studies of this area.

ACC Sulcal Patterns and Their Modulation on Cognitive Control Efficiency Across Lifespan: A Neuroanatomical Study on Bilinguals and Monolinguals

“…The distribution of the ACC sulcal pattern was significantly affected by hemispheric laterality, with the "double parallel" type more frequently present than absent on the left hemisphere and more frequently absent than present on the right (Table 2). This leftward bias largely confirms previous data from postmortem studies of healthy brain specimens (Ide et al 1999) and structural MRI investigations of intact living brains (Paus 1996;Yücel et al 2001;Fornito et al 2004;Huster et al 2007;Leonard et al 2009;Wei et al 2017). Remarkably, prior work on psychiatric populations with CC deficits failed to report comparable laterality effects, showing a reduced degree of leftward PCS asymmetry in patients versus healthy controls (Marquardt et al 2002;Le Provost et al 2003;Yücel et al 2002;2003a;Fujiwara et al 2007) and a reduced PCS extent in hallucinating patients versus nonhallucinating patients and healthy controls (Garrison et al 2015).…”

“…Based on previous accounts (Paus et al 1996;Yücel et al 2001) we expect a significant effect of ACC sulcal pattern driven by a prevalence of leftward PCS asymmetry. As the available evidence is respectively mixed (Ide et al 1999;Yücel et al 2001;Leonard et al 2009) or insufficient (Wei et al 2017), we do not have specific predictions for the effects of gender and ethnicity on ACC sulcal variability. On the other hand, consistent with findings from studies in monolinguals using conflict-related tasks such as the Stroop and the Flanker (Huster et al 2009;Borst et al 2014;Cachia et al 2017), we predict monolinguals' performance to be shaped by ACC sulcal pattern, with leftward PCS asymmetry associated with a performance advantage as compared with the other patterns of ACC sulcation.…”

“…An asymmetry index based on the "single"/"double parallel" type classification was used to assess the distribution of the PCS across the 2 hemispheres (0 = "single/single," i.e., cingulate sulcus only in both hemispheres; 1 = "double parallel/ double parallel," i.e., cingulate sulcus and additional PCS in both hemispheres; 2 = "double parallel/single," i.e., leftward PCS asymmetry; 3 = "single/double parallel," i.e., rightward PCS asymmetry). Incidence rates (%) are calculated within groups and reported in brackets previous studies failed to detect gender-related effects on ACC sulcation (Ide et al 1999;Wei et al 2017), whereas others reported greater leftward PCS asymmetry in males versus females (Yücel et al 2001;Whittle et al 2009;Clark et al 2010) or in females versus males (Leonard et al 2009). These inconsistencies are reflected in morphometric analyses of global (i.e., whole-brain) and localized (i.e., lobe-wise) effects of sexual dimorphism on the convolutional properties of the cerebral cortex (Zilles et al 1988;Luders et al 2004;Im et al 2008;Toro et al 2008).…”

“…These inconsistencies are reflected in morphometric analyses of global (i.e., whole-brain) and localized (i.e., lobe-wise) effects of sexual dimorphism on the convolutional properties of the cerebral cortex (Zilles et al 1988;Luders et al 2004;Im et al 2008;Toro et al 2008). It should be further noted that a few studies found an interaction between gender and handedness, with righthanded males and left handed females showing greater prevalence of leftward PCS asymmetry than left handed males and right-handed females (Huster et al 2007;Wei et al 2017). As our participants were all right handers, we were unable to test whether hand preference interacted with gender membership in modulating ACC sulcation.…”

“…Previous morphometric studies have reported global and regional differences in brain structure between Caucasian and Eastern populations such as Chinese, Koreans and Japanese (Lee et al 2005;Tang et al 2010;Uchiyama et al 2013;Rao et al 2017), which has led to the development of brain atlases specific to ethnicity (e.g., Chinese: Tang et al 2010;Japanese: Uchiyama et al 2013). To our knowledge, Wei et al (2017) is the only study that explored whether ethnicity interferes with ACC sulcation by contrasting Caucasian (German and Belgian) and East Asian (Chinese) participants. In line with our results, no significant differences in ACC folding were reported as a function of ethnic group membership.…”