experience of pain. it appears to be involved in the emotional reaction to pain rather than to the perception of pain itself. evidence from social neuroscience studies have suggested that, in addition to its role in physical pain, the acc may also be involved in monitoring painful social situations as well, such as exclusion or rejection. when participants felt socially excluded in an fmri virtual ball throwing game in which the ball was never thrown to the participant, the acc showed activation. further, this activation was correlated with a self-reported measure of social distress, indicating that the acc may be involved in the detection and monitoring of social situations which may cause social/emotional pain, rather than just physical pain. pathology studying the effects of damage to the acc provides insights into the type of functions it serves in the intact brain. behavior that is associated with lesions in the acc includes: inability to detect errors, severe difficulty with resolving stimulus conflict in a stroop task, emotional instability, inattention, and akinetic mutism. there is evidence that damage to acc is present in patients with schizophrenia, where studies have shown patients have difficulty in dealing with conflicting spatial locations in a stroop-like task and having abnormal erns. participants with adhd were found to have reduced activation in the dorsal area of the acc when performing the stroop task. together, these findings corroborate results from imaging and electrical studies about the variety of functions attributed to the acc. ocd there is evidence that this area may have a role in obsessive–compulsive disorder due to the fact that what appears to be an unnaturally low level of glutamate activity in this region has been observed in patients with the disorder, in contrast to many other brain regions that are thought to have excessive glutamate activity in ocd. recent sdm meta-analyses of voxel-based morphometry studies comparing people with ocd and healthy controls has found people with ocd to have increased grey matter volumes in bilateral lenticular nuclei, extending to the caudate nuclei, while decreased grey matter volumes in bilateral dorsal medial frontal/anterior cingulate cortex. these findings contrast with those in people with other anxiety disorders, who evince decreased (rather than increased) grey matter volumes in bilateral lenticular / caudate nuclei, while also decreased grey matter volumes in bilateral dorsal medial frontal / anterior cingulate gyri. anxiety the acc has been suggested to have possible links with social anxiety, along with the amygdala part of the brain, but this research is still in its early stages. a more recent study, by the wake forest baptist medical centre, confirms the relationship between the acc and anxiety regulation, by revealing mindfulness practice as a meditator for anxiety precisely through the acc. depression the adjacent subcallosal cingulate gyrus has been implicated in major depression and research indicates that deep-brain stimulation of the region could act to alleviate depressive symptoms. although people with depression had smaller subgenual accs, their accs were more active when adjusted for size. this correlates well with increased subgenual acc activity during sadness in healthy people, and normalization of activity after successful treatment. of note, the activity of the subgenual cingulate cortex correlates with individual differences in negative affect during the baseline resting state; in other words, the greater the subgenual activity, the greater the negative affectivity in temperament. lead exposure a study of brain mris taken on adults that had previously participated in the cincinnati lead study found that people that had higher levels of lead exposure as children had decreased brain size as adults. this effect was most pronounced in the acc (cecil et al., 2008) and is thought to relate to the cognitive and behavioral deficits of affected individuals. autism impairments in the development of the anterior cingulate, together with impairments in the dorsal medial-frontal cortex, may constitute a neural substrate for socio-cognitive deficits in autism, such as social orienting and joint attention. ptsd an increasing number of studies are investigating the role of the acc in post-traumatic stress disorder. ptsd diagnosis and related symptoms such as skin conductance response (scr) to "potentially startling sounds" were found to be correlated with reduced acc volume. further, childhood trauma and executive dysfunction seem to correlate with reduced acc connectivity to surrounding neural regions. in a longitudinal study, this reduced connectivity was able to predict high-risk drinking (binge drinking at least once per week for the past 12 months) up to four years later. general risk of psychopathology a study on differences in brain structure of adults with high and low levels of cognitive-attentional syndrome demonstrated diminished volume of the dorsal part of the acc in the former group, indicating relationship between cortical thickness of acc and general risk of psychopathology. additional images medial surface of human cerebral cortex - gyri anterior cingulate cortex of monkey (macaca mulatta). caudal anterior cingulate gyrus rostral anterior cingulate gyrus