The anterior midcingulate cortex as a neural node underlying hostility in young adults.

Anger typically manifests for only a short period of time, whereas hostility is present for a longer duration. However, both of these emotions are associated with an increased likelihood of psychological problems. The nodes within the neural networks that underlie hostility remain unclear. We presumed that specific nodes might include the anterior midcingulate cortex (aMCC), which seems to be essential for the cognitive aspects of hostility. Thus, the present study first evaluated the associations between regional gray matter density (rGMD) and hostility in 777 healthy young students (433 men and 344 women; 20.7 ± 1.8 years of age) using magnetic resonance imaging and the hostile behaviors subscale (HBS) of the Coronary-prone Type Scale (CTS) for Japanese populations. The HBS scores were positively correlated with rGMD in the aMCC and in widespread frontal regions from the dorsomedial/dorsolateral prefrontal cortices to the lateral premotor cortex at the whole-brain level. No significant correlation was observed between rGMD and the conjunction of HBS and Trait Anger/Anger-Out scores. Furthermore, no significant interaction effects of sex and HBS scores on rGMD were revealed, although the HBS scores of males were significantly higher than those of females. The present findings indicate that the neural correlates of hostility appear to be more distinct in rGMD than those of anger due to differences and duration.