The cingulate gyrus is a turn of the cerebrum (telencephalon). It forms part of the limbic system and participates in cognitive and emotional functions. The brain structure is associated with various mental disorders such as schizophrenia, obsessive-compulsive disorder, and depression.
What is the cingulate gyrus?
With the help of its neural networks, the brain controls central processes of the organism. In humans, the cerebrum, also known as the telencephalon, makes up the majority of the brain‘s mass. Compared to the central nervous system of other animals, the human brain is very developed. As a result, it is capable of performing not only control processes but also higher cognitive functions. Furthermore, the cerebrum is considered the seat of personality. The brain mass does not represent a homogeneous substance, but is composed of numerous smaller structures. In anatomy, the gray matter is the area in which cell bodies are predominantly located. In contrast, the white matter consists of myelinated nerve fibers. The cortex of the cerebrum consists of gray matter and has furrows (sulci) and convolutions (gyri). The cingulate gyrus is one such turn of the telencephalon. It is located in the center of the brain. Below it is the bar (corpus callosum).
Anatomy and structure
The cingulate gyrus can be divided into different areas. The anterior area is formed by the pars anterior, which contains numerous spindle cells. Its area corresponds to Brodmann’s area 24. Sometimes anatomy also additionally counts areas 32 and 33 as part of the pars anterior. Other subdivisions, however, consider Brodmann area 32 as an independent part of the cingulate gyrus. This region represents the cingulate motor area. In contrast to the pars anterior, the pars posterior lies in the posterior part of the cingulate gyrus It consists of Brodmann area 23 and occasionally includes field 31. This lies adjacent to both Brodmann area 23 and area 24. The pars posterior may not represent a unitary brain structure. Instead, research provides evidence that an anterior and a dorsal subunit can be distinguished based on different functions. According to some divisions, anatomy still counts a third or fourth area as part of the cingulate gyrus. This part is the Zuckerkandl turn (area subcallosa) and corresponds to Brodmann area 25.
Function and tasks
The cingulate gyrus exerts various cognitive and emotional functions. Not all areas of the cerebral cingulate are active at the same time; in fact, the individual areas can be further distinguished based on their functions. The pars anterior of the cingulate gyrus consists of a dorsal and a ventral portion. The ventral portion is associated with emotional functions and maintains connections to the amygdala, nucleus accumbens, insula, and hypothalamus. The dorsal part, on the other hand, is where more cognitive processes take place. The neuronal connections to the prefrontal and parietal cortex as well as to visual and motor processing centers reflect the cognitive tasks. The Stroop test (color interference test) and other severe cognitive tasks are associated with increased activation of the pars anterior of the cingulate gyrus. The pars posterior communicates with the pars anterior, caudate nucleus, orbitofrontal and intraparietal cortex, precuneus, and parts of the thalamus. The pars posterior responds to emotional stimuli and is active in the retrieval of autobiographical memories. In addition, the pars posterior plays a role in intrinsic cognitive control. It is associated with other learning and memory processes such as spatial memory and attentional processes. In addition, the pars posterior has connections to the temporal lobe (lobus temporalis) and may also influence memory processes through this pathway.
Diseases
The cingulate gyrus is associated with several mental disorders. One of these is schizophrenia, whose symptoms include various forms of hallucinations, ego disorders, and delusions. In addition, this psychotic disorder is associated with negative symptoms such as flattening of emotions and affect, social withdrawal, impoverishment of speech, and apathy. People with schizophrenia have on average less gray matter in the pars anterior of the gyrus cinguli than a healthy control group.Furthermore, the size of the pars anterior correlates with the social functioning level of the affected person. Schizophrenia also appears to be associated with a low metabolic rate in the cingulate gyrus. The cingulate gyrus may also be related to obsessive-compulsive disorder. Obsessive-compulsive disorder is characterized by actions and thoughts that the sufferer is unable to suppress, despite being aware of their futility. Common forms of these mental disorders revolve around compulsions to wash or control. In contrast to normal habits, compulsions are characterized by the fact that they lead to considerable impairment or suffering for the person affected. They also take up a lot of time. In depression, functional abnormalities involve the cingulate gyrus, especially in the pars posterior. The two core features of depression are depressed mood and loss of pleasure or interest in (almost) anything. A radical treatment option that may be used as a last resort for particularly severe disorders is cingulotomy. In this procedure, the surgeon cuts the cingulate gyrus, nowadays often with the help of the gamma knife or other radiation. This procedure is irreversible and results in permanent psychological changes that go beyond the disorder. Cingulotomy is used primarily for obsessive-compulsive disorder, when other treatments fail and the compulsions have a severe impact on the person’s life.
