Cingulate gyrus (brain): anatomy and functions

The cingulate gyrus, also known as the cingulate gyrus, gyrus of the cingulate, cingulum or gyrus cinguli It is a very important part of the brain, as it performs an essential connecting role between the limbic system and the neocortex. The cingulate gyrus forms an arcuate gyrus, close to the surface of the hard body.

In simplistic terms, the cingulate gyrus is like a “passing” structure, like a bridge, which greatly differentiates us from animals that have evolved differently from ours.

It connects the structures that equate us to other animals (the limbic system: let's remember the importance of the hippocampus and the amygdala) and to those that give us the ability to plan, reason, make conceptual abstractions: the higher cognitive functions located in the neocortex.

Functions of the cingulate gyrus

The anterior cingulate region has important connections with the amygdala, hippocampus, septum, anterior hypothalamus, caudate and putamen, dorso-medial nucleus of the thalamus, inferior parietal lobe, lateral convexity, and medial frontal lobes.

• It plays a connecting role between volitional, cognitive, emotional and mnestic motor aspects.
• It deals with modulating and processing the expression of subtle emotional nuances
• It intervenes in the modulation of the voice (sadness, happiness).
• It is responsible for the learning of emotional vocalization, which facilitates the formation of long-term attachments, especially the attachment between mother and child.
• Its stimulation produces feelings of anxiety, pleasure and fear.
• It is responsible for initiating the behavior oriented to motivational goals significant for the subject.
• The subcallosal region is responsible for the regulation of autonomic functions such as respiration and heart rate.
• Participates in hand movements and other movements in difficult tasks, or that involve recent memory, and in the spontaneous initiation of action.
• It is activated in situations that demand executive control, divided attention, resolution of conflicts, error detection, response monitoring, and response initiation and maintenance appropriate.
• It plays a basic role in the selective attention involved in the correct resolution of the Stroop test and in other attentional tasks guided by motivation. The function would be to monitor the conflict between stimulus and response to select the appropriate behavior.
• It plays an important role related to motivation in the functioning of the prefrontal cortex for the performance of voluntary actions.

The circuit of Papez

Papez (1929) stated that communication between the hippocampus and the neocortex takes place reciprocally.

They are constantly connected by means of the cingulate gyrus, and it would be carried out in the following way: the formation hippocampal processes the information that comes from the cingulate gyrus, and carries it to the mammillary bodies of the hypothalamus (a through the fornix).

At the same time, the hypothalamus sends information to the cingulate gyrus via the mammillary bodies-anterior thalamic nucleus and from there to the frontal cortex.

The processing of the conflict

Posner and other authors (2007) have ensured that the anterior cingulate gyrus is part of an attentional network executive, which is responsible for regulating the processing of information from other sensory networks and emotional This is important in order to carry out a task, especially those that require effort or those that are new (not routine).

Some authors, such as Posner and Botvinick, propose the conflict monitoring hypothesis, which argues that when a conflict detection occurs in a task (as in the Stroop test), the anterior cingulate gyrus puts into action a set of strategic adjustments in cognitive control and in planning the response.

Your goal is to reduce the conflict in the task and, the next time, get it right. It's like a controlled mechanized evaluation of results. If these are not satisfactory, information is sent to other structures of the planning system (frontoparietal system and cerebellum) that are responsible for establishing action strategies and learning from error.

Emotional control mechanism

According to Kandel (2000), the emotional state of humans is made up of physical sensations and specific feelings, and they are regulated by different anatomical structures.

Concrete feelings are regulated by the cingulate cortex and the orbitofrontal cortex, and emotional states (responses peripheral, autonomic, endocrine, and skeletal-motor) involve subcortical structures such as the amygdala, hypothalamus, and stem cerebral. For example, when we watch a horror movie and feel fear, at the same time we experience an increase in heart rate, our mouth becomes dry, our muscles tense, and so on.

The rostral anterior cingulate cortex can help to inhibit the activity of the amygdala, resolve emotional conflicts. This phenomenon is called "emotional top-down". In patients with depression there is hyperactivation of the anterior cingulate cortex in the processing of negative self-referential words. More specifically, there is a positive correlation between the amygdala, the medial prefrontal cortex and the rostral cingulate cortex between the processing of negative self-referential emotional information.

People with Post Traumatic Stress Disorder, show hypoactivity of the rostral anterior cingulate cortex when trying to evoke the trauma and during its reexperience. Furthermore, the severity of PTSD symptoms correlates with the underactivity of the rostral anterior cingulate cortex.

In people with anxiety, there is no suppression of the activity of the amygdala, which is negatively correlated with the activity of the rostral anterior cingulate cortex. The changes in this activity will depend on the perceived threat, the degree of helplessness that the person feels and the anticipation of adverse stimuli.

What happens if the cingulate gyrus is injured?

His injury produces various disorders and syndromes, such as mutism, imitation behaviors (echopraxia) and compulsive use of objects.

Lesions in the anterior and medial cingulate regions generate exploratory, attentional, or action motivation disorders. Injured patients show hypokinesia, apathy, apathy without depression, lack of spontaneity, akinetic mutism, and a flattened emotional response.

Bilateral cingulate injuries generate sphincter incontinence, a tendency towards distraction, to docility and fantasy.

The most well-known alteration when the cingulate gyrus is injured is the medial frontal or anterior cingulate syndrome, which is characterized by lack of initiative, akinesia or hypokinesia, apathy and mutism. There is a reduction in goal-oriented activities, patients do not show interest or concern for anything (not for their family, not themselves or the future).

It would also have to do with the dependency syndrome on the environment, which entails the loss of personal autonomy (entails a tendency to distraction, hyper-reactivity, decreased motivation and apathy).

Bibliographic references:

• Guyton, AC; Hall, JE. (2006). Medical Physiology, Elsevier Saunders. 11th edition.
• MacLean, P. D. (January 31, 1990). The Triune Brain in Evolution: Role in Paleocerebral Functions. Springer Science & Business Media.
• Pinel, J. (2004). Biopsychology. Madrid: Pearson Prentice Hall.