http://www.mayo.edu/research/discoverys-edge/genomics-bipolar-disorder
The anterior cingulate cortex (ACC) is the frontal part of the cingulate cortex, which resembles a "collar" surrounding the frontal part of the corpus callosum.
It appears to play a role in a wide variety of autonomic functions, such as regulating blood pressure and heart rate... It is also involved in rational cognitive functions, such as reward anticipation, decision-making, empathy, impulse control, and emotion.
A typical task that activates the ACC involves eliciting some form of conflict within the participant that can potentially result in an error.
One such task is called the Eriksen flanker task and consists of an arrow pointing to the left or right, which is flanked by two distractor arrows creating either compatible (<<<<<) or incompatible (<<<>>) trials. Another very common conflict-inducing stimulus is the Stroop task (Pardo et al., 1990), which involves naming the color ink of words that are either congruent (RED written in red) or incongruent (RED written in blue). Conflict occurs because people’s reading abilities interfere with their attempt to correctly name the word’s ink color. A variation of this task is the Counting-Stroop, during which people count either neutral stimuli (‘dog’ presented four times) or interfering stimuli (‘three’ presented four times) by pressing a button...
Many studies attribute specific functions such as error detection, anticipation of tasks, attention, motivation, and modulation of emotional responses to the ACC.
http://en.wikipedia.org/wiki/Anterior_cingulate_cortex
A... study suggests that people’s ability to distinguish between what really happened and what was imagined may be determined by the presence of a fold at the front of the brain that develops late in pregnancy, and is missing entirely in 27% of people.
The key brain structure identified by the study is called the paracingulate sulcus (PCS), a fold in part of the prefrontal cortex, the region that is involved with planning, thought and judgment. The size of the PCS varies greatly in normal people, and some people have a PCS only on one side of their brain, while others have one on both.
... studies like this cannot determine whether having a small or absent PCS causes difficulties with reality recognition memories, or whether the effect works the other way around.
http://books.google.se/books?id=WQVviYqU-IcC&pg=PA70&lpg=PA70&dq=anterior+cingulate+psychosis&source=bl&ots=3Qu_QIraPk&sig=aR95bFI_OgN9J6H6TiqF7uwz4OM&hl=en&sa=X&ei=DW3EUou8IarJ4gTR14HIBQ&ved=0CGgQ6AEwBw#v=onepage&q=anterior%20cingulate%20psychosis&f=false
