Anterior Cingulate Cortex - Pathology

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.

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 strange 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.

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.

The adjacent subcallosal cingulate gyrus has been conjectured to play an important role in major depression and has been the target of deep brain stimulation to treat that disease.

A 2008 study of brain MRIs taken on adults that had previously participated in the Cincinnati Lead Study demonstrated that people that had suffered higher levels of lead poisoning 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.