Instruct: Given a question, retrieve relevant documents that can help answer the question.
Query: What is the primary function of the anterior cingulate cortex?
It appears to play a role in a wide variety of autonomic functions, such as regulating blood pressure and heart rate.
People with schizophrenia have differences in the anterior cingulate gyrus when compared with controls. The anterior cingulate gyrus was found to be smaller in people with schizophrenia. The volume of the gray matter in the anterior cingulate gyrus was found to be lower in people with schizophrenia. Healthy females have larger rostral anterior cingulate gyrus than males, this sex difference in size is absent in people with schizophrenia. The metabolic rate of glucose was lower in the left anterior cingulate gyrus and in the right posterior cingulate gyrus.
Another cause of both akinesia and mutism is ablation of the cingulate gyrus. Destruction of the cingulate gyrus has been used in the treatment of psychosis. Such lesions result in akinesia, mutism, apathy, and indifference to painful stimuli. The anterior cingulate cortex is thought to supply a "global energizing factor" that stimulates decision making. When the anterior cingulate cortex is damaged, it can result in akinetic mutism.
The somatosensory cortex encodes incoming sensory information from receptors all over the body. Affective touch is a type of sensory information that elicits an emotional reaction and is usually social in nature, such as a physical human touch. This type of information is actually coded differently than other sensory information. Intensity of affective touch is still encoded in the primary somatosensory cortex, but the feeling of pleasantness associated with affective touch activates the anterior cingulate cortex more than the primary somatosensory cortex. Functional magnetic resonance imaging (fMRI) data shows that increased blood oxygen level contrast (BOLD) signal in the anterior cingulate cortex as well as the prefrontal cortex is highly correlated with pleasantness scores of an affective touch. Inhibitory transcranial magnetic stimulation (TMS) of the primary somatosensory cortex inhibits the perception of affective touch intensity, but not affective touch pleasantness. Therefore, the S1 is not directly involved in processing socially affective touch pleasantness, but still plays a role in discriminating touch location and intensity.
Neuroimaging also uncovered different sub-regions in the anterior cingulate cortex itself based on their function. These studies showed that the caudal part of the anterior cingulate cortex plays a more important function in cognitive activities that involve attention, salience, interference and response competition. These results combined with electrophysiological investigation of the function of neurons in the anterior cingulate cortex have provided insights that can be used in the improvement of cingulotomy performed on patients treated for OCD. The basis behind this idea is the fact that a variation of certain tasks, Emotional Stroop tasks (ES), which have been particularly identified as exerting effects in OCD patients activate neurons in the more rostral part of the anterior cingulate cortex. Thus, theoretically if bilateral cingulotomy is performed in such patient in the rostral anterior cingulate cortex, better results should be obtained.
This corresponds to areas 24, 32 and 33 of Brodmann and LA of Constantin von Economo and Bailey and von Bonin. 
It is continued anteriorly by the subgenual area (Brodmann area 25), located below the genu of the corpus callosum).
It is cytoarchitectonically agranular. It has a gyral and a sulcal part. 
Anterior cingulate cortex can further be divided in the perigenual anterior cingulate cortex (near the genu) and midcingulate cortex. The anterior cingulate cortex receives primarily its afferent axons from the intralaminar and midline thalamic nuclei (see thalamus). 
The nucleus anterior receives mamillo-thalamic afferences. The mamillary neurons receive axons from the subiculum. 
The whole forms a neural circuit in the limbic system known as the Papez circuit.
The anterior cingulate cortex sends axons to the anterior nucleus and through the cingulum to other Broca's limbic areas. The ACC is involved in error and conflict detection processes.
Moreoever, the posterior dorsal anterior cingulate cortex is responsible for what decision is made (i.e. whether you will say the incorrect answer [written word] or the correct answer [ink color]). Following the response, the anterior dorsal anterior cingulate cortex is involved in response evaluation—deciding whether the answer is correct or incorrect. Activity in this region increases when the probability of an error is higher.
Another neural model for voluntary action also involves what, when, and whether (WWW) based decisions.
The 'what' component of decisions is considered a function of the anterior cingulate cortex, which is involved in conflict monitoring. The timing ('when') of the decisions are considered a function of the preSMA and SMA, which is involved in motor preparation.
Finally, the 'whether' component is considered a function of the dorsal medial prefrontal cortex.
One theory discussed found that "Aha" answers produced more negative ERP results, N380 in the ACC, than the "No-Aha" answers, 250–500 ms, after an answer was produced. The authors suspected that this N380 in the ACC, which plays the role of a warning sign of breaking the mental set, was a reflection of the Aha! effect. Another study was done showed that an Aha! effect was elicited at N320 which has a strong activation in the central-posterior region. These previous studies reflective the premise of the study, that the Aha! effect occurs in the anterior cingulate cortex, while this study finds results indicating the posterior cingulate cortex is responsible. It was found that there was a N350 in the posterior cingulate cortex for successful guessing of logographs, not in the anterior cingulate cortex. The posterior cingulate cortex seems to play a more non-executive function in monitoring and inhibiting the mind set and cognitive function.
Functional neuroimaging research suggests the insula is involved in two types of salience. Interoceptive information processing that links interoception with emotional salience to generate a subjective representation of the body. This involves, first, the anterior insular cortex with the pregenual anterior cingulate cortex (Brodmann area 33) and the anterior and posterior mid-cingulate cortices, and, second, a general salience network concerned with environmental monitoring, response selection, and skeletomotor body orientation that involves all of the insular cortex and the mid-cingulate cortex.
It has been stated that "The cognitive consequences of anterior cingulate lesions remain rather equivocal, with a number of case reports of intact general neuropsychological and executive function in the presence of large anterior dorsal cingulate lesions.[24] For an alternative view of anterior cingulate, see Rushworth's review (2007).[25]
A 2008 review by Weber et al. suggested that psychopathy is sometimes associated with brain abnormalities in prefrontal-temporo-limbic regions that are involved in emotional and learning processes, among others. Neuroimaging studies have found structural and functional differences between those scoring high and low on the PCL-R in a 2011 review by Skeem et al. stating that they are "most notably in the amygdala, hippocampus and parahippocampal gyri, anterior and posterior cingulate cortex, striatum, insula, and frontal and temporal cortex". A 2010 meta-analysis found that antisocial, violent and psychopathic individuals had reduced structure function in the right orbitofrontal cortex, right anterior cingulate cortex and left dorsolateral prefrontal cortex.
The posterior cingulate cortex (Brodmann's area 23) sends projections to dorsolateral prefrontal cortex (Brodmann's area 9), anterior prefrontal cortex (Brodmann's area 10), orbitofrontal cortex (Brodmanns’ area 11), the parahippocampal gyrus, posterior part of the inferior parietal lobule, the presubiculum, the superior temporal sulcus and the retrosplenial region.
The retrosplenial cortex and caudal part of the cingulate cortex are connected with rostral prefrontal cortex via cingulate fascicule in macaque monkeys Ventral posterior cingulate cortex was found to be reciprocally connected with the caudal part of the posterior parietal lobe in rhesus monkeys. Also the medial posterior parietal cortex is connected with posterior ventral bank of the cingulate sulcus.
Medial surface of human cerebral cortex - gyri Anterior Cingulate Cortex of monkey (Macaca mulatta).
The posterior cingulate cortex is the backmost part of the cingulate cortex, lying behind the anterior cingulate cortex. The PCC forms a part of the posteromedial cortex, along with the retrosplenial cortex (Brodmann areas 29 and 30) and precuneus (located posterior and superior to the PCC). The PCC, together with the retrosplenial cortex, forms the retrosplenial gyrus. The posterior cingulate cortex is bordered by the following brain regions: the marginal ramus of the cingulate sulcus (superiorly), the corpus callosum (inferiorly), the parieto-occipital sulcus (posteriorly), and Brodmann area 24 (anteriorly).
Functional MRI analyses of the anterior cingulate cortex have also led to the introduction of bilateral cingulotomy for the treatment of chronic pain. Such application was introduced since the anterior cingulate cortex has been found to be related to the processing nociceptive information input. In particular the role of the anterior cingulate cortex is in the interpretation of how a stimulus affects a person rather than its actual physical intensity.
The anterior cingulate is connected to the posterior cingulate at least in rabbits. Posterior cingulate gyrus is connected with retrosplenial cortex and this connection is part of the dorsal splenium of the corpus callosum. The anterior and posterior cingulate gyrus and retrosplenial cortex send projections to subiculum and presubiculum.
Functional neuroimaging studies have implicated multiple regions in OCD. Symptom provocation is associated with increased likelihood of activation in the bilateral orbitofrontal cortex(OFC), right anterior PFC, left dorsolateral prefrontal cortex (dlPFC), bilateral anterior cingulate cortex (ACC), left precuneus, right premotor cortex, left superior temporal gyrus(STG), bilateral external globus pallidus, left hippocampus, right insula, left caudate, right posterior cingulate cortex (PCC), and right superior parietal lobule. During affective tasks hyperactivation has been observed in the ACC, insula and head of the caudate and putamen, regions implicated in salience, arousal, and habit. Hypoactivation during affective tasks is observed in the medial prefrontal cortex (mPFC) and posterior caudate, which are implicated in behavioral and cognitive control. During non-affective tasks, hyperactivation has been observed in the precuneus and PCC, while hypoactivation has been observed in the pallidum, ventral anterior thalamus and posterior caudate. An older meta analysis found hyperactivity in the OFC and ACC. An ALE meta analysis of various functional neuroimaging paradigms observed various abnormalities during Go/no go, interference, and task switching paradigms. Decreased likelihood of activation in right putamen and cerebellum was reported during Go/no go. During interference tasks, likelihood of activation was reported in the left superior frontal gyrus, right precentral gyrus, and left cingulate gyrus, to be decreased, and in the right caudate to be increased. Task switching was associated with extensive decreased likelihood of activation in the middle, medial, inferior, superior frontal gyri, caudate, cingulate and precuneus. A separate ALE meta analysis found consistent abnormalities in orbitofrontal, striatal, lateral frontal, anterior cingulate, middle occipital and parietal, and cerebellar regions.
Studies in patients that were a subject to bilateral cingulotomy, that involved fMRI analyses, showed that the anterior cingulate cortex has a key role in cognitive control and is highly likely to be involved in the control of attentional response, whereas the dorsal part of that region of the brain was not identified to be involved in such a process, although this is still under dispute. The function of the dorsal part of the cingulate cortex was connected to the sorting out and processing of conflicting information signals. In addition, neuroimaging studies also indicated that the anterior cingulate cortex participates in the modulation of cortical regions that are of higher order as well as sensory processing areas.
Meanwhile, the feeling of pleasantness associated with affective touch activates the anterior cingulate cortex more than the primary somatosensory cortex. Functional magnetic resonance imaging (fMRI) data shows that increased blood oxygen level contrast (BOLD) signal in the anterior cingulate cortex as well as the prefrontal cortex is highly correlated with pleasantness scores of an affective touch. Inhibitory transcranial magnetic stimulation (TMS) of the primary somatosensory cortex inhibits the perception of affective touch intensity, but not affective touch pleasantness. Therefore, the S1 is not directly involved in processing socially affective touch pleasantness, but still plays a role in discriminating touch location and intensity.
In the human this area is known as ventral anterior cingulate area 24, and it refers to a subdivision of the cytoarchitecturally defined cingulate cortex region of cerebral cortex (area cingularis anterior ventralis). It occupies most of the anterior cingulate gyrus in an arc around the genu of the corpus callosum. Its outer border corresponds approximately to the cingulate sulcus. Cytoarchitecturally it is bounded internally by the pregenual area 33, externally by the dorsal anterior cingulate area 32, and caudally by the ventral posterior cingulate area 23 and the dorsal posterior cingulate area 31.
The rostral cingulate gyrus (Brodmanns's area 32) projects to the rostral superior temporal gyrus, midorbitofrontal cortex and lateral prefrontal cortex.
The ventral anterior cingulate (Brodmann's area 24) sends projections to the anterior insular cortex, premotor cortex (Brodmann's area 6), Brodmann's area 8, the perirhinal area, the orbitofrontal cortex (Brodmann's area 12), the laterobasal nucleus of amygdala, and the rostral part of the inferior parietal lobule. Injecting wheat germ agglutinin and horseradish peroxidase conjugate into the anterior cingulate gyrus of cats, revealed that the anterior cingulate gyrus has reciprocal connections with the rostral part of the thalamic posterior lateral nucleus and rostral end of the pulvinar.
The postsubiculum receives projections from the retrospleinal dysgranular cortex and the retrosplenial granular cortex A and B. The parasubiculum receives projections from the retrosplenial dysgranular cortex and retrosplenial granular cortex A. Caudal and lateral parts of the entorhinal cortex get projections from the retrosplenial dysgranular cortex, while the caudal medial entorhinal cortex receives projections from the retrosplenial granular cortex A. The retrosplenial dysgranular cortex sends projections to the perirhinal cortex. The retrospleinal granular cortex A sends projection to the rostral presubiculum.
Not much is known about the exact function of these areas in the tip-of-the-tongue phenomenon. The areas activated during TOT may vary depending on the nature of the target word. For example, if the target word is a person's name, the fusiform face area will likely show activation as the rememberer processes the person's face. Problems like this make it difficult to determine what areas are specifically implicated in TOT states, and which are a byproduct of other cognitive functions. However, some inferences can be made about the roles of these structures based on theories of their functions derived from other studies of these structures, unrelated to TOT. It is hypothesized that the anterior cingulate cortex and the right dorsolateral prefrontal cortex operate as a circuit to detect conflict, and may perform this role in detecting the conflict between the feeling of knowing the target word and the recall failure. The anterior cingulate cortex is also implicated in emotion and may show activation because of the emotional response to the tip of the tongue state. The posterior medial parietal cortex, bilateral lateral parietal cortex, and the bilateral superior prefrontal cortex are involved in retrieval and evaluation, and therefore may play a role in the metacognitive processes involved in the tip of the tongue phenomenon such as the evaluation of one's own knowledge and the probability of retrieval.
Cingulate cortex Cingulate gyrus Cingulate sulcus subgenual cingulate cortex subcallosal cortex Reward system
In March 2010, the Royal College of Obstetricians and Gynecologists submitted a report, concluding that "Current research shows that the sensory structures are not developed or specialized enough to respond to pain in a fetus of less than 24 weeks", pg. 22. The neural regions and pathways that are responsible for pain experience remain under debate but it is generally accepted that pain from physical trauma requires an intact pathway from the periphery, through the spinal cord, into the thalamus and on to regions of the cerebral cortex including the primary sensory cortex (S1), the insular cortex and the anterior cingulated cortex.3,4 Fetal pain is not possible before these necessary neural pathways and structures (figure 1) have developed. -pg. 3 The report specifically identified the anterior cingulate as the area of the cerebral cortex responsible for pain processing. The anterior cingulate is part of the cerebral cortex, which begins to develop in the fetus at week 26.