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

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.