Fri. Aug 12th, 2022

    Cingulate gyrus or cingulate cortex

    The function is cingulate gyrus is involved in processing emotions and behavior regulation. It also helps to regulate autonomic motor function.

    When we are worried or anxious, it is our cingulate gyrus that acts. It helps us to express our emotional state through gesture, posture and movement.

    As you can imagine, the cingulate gyrus has grown in importance in neurocognitive and cognitive studies. In addition, this part of the brain’s anatomy has been linked to various brain functions, but also to certain disorders.

    Alzheimer’s disease or depression are good examples. However, there are also other disorders such as schizophrenia, bipolar disorder, some anxiety disorders and others related to substance abuse.

    The cingulate gyrus is a limbic lobe gyrus of the cerebral cortex. It is located on the medial aspect of the hemispheres, above the corpus callosum. Above, it is separated from the superior frontal gyrus by the cingulate sulcus and from the precuneus by the subparietal sulcus. Below, its limit is the furrow of the corpus callosum. At the level of the splenium of the corpus callosum, the cingulate gyrus narrows into the isthmus which continues through the parahippocampal gyrus.

    Read also: Brain Gyrus (Cerebral cortex) and Sulcus (Neuroanatomy) | Important features of the central nervous system

    The whole cingulate gyrus, parahippocampal gyrus and various olfactory formations form an almost closed ring which is called gyrus fornicatus (in Latin, fornicatus means “arched, arched”).

    The cingulate gyrus (from the Latin gyrus ‘twist’ and cingulum ‘belt’) or belt twist is a part of the brain and functionally belongs to the limbic system. It is a structure of the telencephalon (endbrain), above the corpus callosum (bar), which connects the medial parts of the hemispheres.

    The cingulate gyrus consists of four sections:

    • Pars anterior = Brodmann area 24
    • Pars posterior = Brodmann area 23
    • Area subcallosa = Brodmann area 25
    • Cingulate motor areas = Brodmann area 32

    A long association path, the cingulum, runs in the medullary bed of the cingulate gyrus . It ends in the cortex of the subiculum of the hippocampus formation.

    Surgical cutting of the cingulate gyrus is known as a cingulotomy .

    Function

    As part of the limbic system, the cingulate gyrus is involved in the development and processing of emotions as well as in learning and memory processes. It seems to play a decisive role in the emotional evaluation of the external environment and its connection with the internal emotional state.

    Compassion and emotional ties are localized here. In the case of disturbances in the general attitude towards life and a negative mood such as depression , changes in neural activity can often be detected here. Skills such as shifting attention, adapting to changes and recognizing options are also localized here.

    Main structure of cingulate gyrus

    1. Anterior cingulate cortex

    Anterior cingulate cortex play a role in a wide variety of autonomic functions such as the regulation of blood pressure and heart rate, cognitive functions, such as reward anticipation, decision making, empathy, and emotion.

    This brain area is particularly active in an individual subject to stress or in paranoid subjects. Studies on ACC are an important starting point for understanding part of the neurobiological correlates of some mental disorders, such as:

    • Schizophrenic behaviors
    • Obsessive-compulsive disorder
    • Paranoia and fixations
    • Disexecutive Syndromes (paying attention, organizing, planning, and prioritizing · Starting tasks and staying focused on them to completion)

    In the case of schizophrenic patients, for example, the cortex does not work in the right way: some inhibitory brakes are lacking which, depending on the case, can determine the most “original” behaviors.

    In the case of obsessive-compulsive patients, the exact opposite happens: the alarm signals of the unconscious are excessive compared to the situation and environment in which the subject is. This means that people with this type of disorder feel the danger where in reality it does not exist or in any case overestimate it compared to the average population.

    From a neuropsychological point of view , a circumscribed lesion to the anterior cingular cortex causes a deficit in the ability to inhibit previously learned responses and in the ability to control the interference effect in the presence of distracting stimuli. For example, the patient scores significantly lower on the Stroop test than the able-bodied subjects.

    2. Medial cingulate cortex

    This part of the cingulate gyrus is involved when we make predictions about behavioral outcomes. It also helps to perform this behavior by projections on the dorsolateral prefrontal cortex, additional motor areas, parietal cortex and spinal cord.

    This is why the medial cingulate cortex is believed to be related to the processing of decision information. In particular, it would be reward-based decision making and cognitive activity associated with intentional motor control.

    3. Posterior cingulate cortex

    The posterior cingulate gyrus is linked to a topokinetic memory circuit. More precisely, its main function is visuospatial orientation.

    The most ventral part appears to be strongly integrated into the brain’s “default mode network”. That is, a system in the brain that stays active when we are not paying attention to external stimuli.

    In addition, it is believed that this part also concerns the cognitive processes directed internally. It could be garbage collection, planning, or processing spatial information.

    It is also assumed that this part participates in self-control and in the evaluation of events related to our own importance.

    The most dorsal part of the posterior cingulate cortex is closely related to the premotor, dorsal visual, and frontal orbital regions of the brain. In addition, this part participates in the orientation of the body in a visual space.

    4. Retrosplenial cortex

    This part of the cingulate gyrus has been involved in processes such as autobiographical memory and the imagination. It therefore appears that many neurological disorders that impair memory are associated with problems in this region of the cingulate gyrus.

    If cingulate gyrus damage

    So it seems that the cingulate gyrus is primarily responsible for mediating our emotional reactions. In addition, he is also responsible for placing value on emotion in the face of external and internal stimuli. In particular, the cingulate gyrus allows us to vocalize internal states (that is, it allows us to express our emotions aloud).

    In conclusion, if the cingulate gyrus is damaged, the autonomic system may lose its ability to respond to conditioned stimuli. This could lead to aggressive behavior, shyness, or reduced feelings of affection.

    The cingulate gyrus is the subject of many cognitive and neurocognitive studies. It has been implicated in eg. Alzheimer’s disease, anxiety disorders, addiction, depression, bipolar disorder and schizophrenia.

    Schizophrenic patients have differences in the anterior cingulate gyrus when compared with controls. Anterior cingulate gyrus was found to be smaller in schizophrenic patients. The volume of the gray matter in the anterior cingulate gyrus was found to be lower in schizophrenic patients

    Early atrophy of the cingulate cortex is a feature of both behavioral variant frontotemporal dementia (bvFTD) and Alzheimer’s disease (AD), with degeneration of the anterior cingulate region increasingly recognized as a strong predictor of bv FTD.

    The ACC (Anterior cingulate cortex) serves as a central “hub” in addiction-related neural networks of cognitive functions, including decision-making, cognitive inhibition, emotion, and motivation. Substance use disorder (SUD) is characterized by compulsive use of addictive substances with considerable impact on both the medical system and society as a whole.  New insights on the anterior cingulate cortex (ACC: Anterior cingulate cortex) suggest neuromodulation targeting the ACC as a way to treat SUD (Substance use disorder).

    In conclusion, damage to the cingulate gyrus may affect the ability to respond to certain stimuli. That could lead to ie. aggressive behavior, shyness, or a decrease in emotional expression.

    Sources: PinterPandai, Science Direct,