The cingulate gyrus (cerebrum): anatomy and functions.

We explain what functions this region of the human brain has.

The cingulate gyrus, also known as the cingulate gyrus, cingulate gyrus, cingulum, cingulum o gyrus cinguli is a very important part of the brain, as it plays an essential connecting role between the limbic system and the neocortex. The cingulate gyrus forms an arcuate gyrus, close to the surface of the corpus callosum.

In simplistic terms, the cingulate gyrus is a kind of "bridge" structure that differentiates us to a great extent from animals that have evolved differently from us.

It connects the structures that put us on a par with other animals (the limbic system: remember the importance of the hippocampus and the amygdala) and those that give us the ability to plan, reason, and 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 motor, emotional and mnestic aspects.
• It is involved in modulating and processing the expression of subtle emotional nuances.
• Involved in voice modulation (sadness, happiness).
• It is responsible for learning 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 behavior oriented to motivational goals that are meaningful to the subject.
• The subcallosal region is responsible for the regulation of autonomic functions such as breathing and Heart rate.
• It is involved in hand movements and other movements in difficult tasks, or those involving recent memory, and in the spontaneous initiation of action.
• It is activated in situations that demand executive control, divided attention, conflict resolution, error detection, response monitoring, and initiation and maintenance of appropriate responses.
• It plays a basic role in 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 stimulus-response conflict in order 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 Papez circuit

Papez (1929) stated that communication between the hippocampus and the neocortex takes place in a reciprocal manner..

They are constantly connected by means of the cingulate gyrus, and it would be carried out as follows: the hippocampal formation processes the information coming from the cingulate gyrus, and carries it to the mammillary bodies of the hypothalamus (through the fornix).

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

Conflict processing

Posner et al. (2007) have stated that the anterior cingulate gyrus is part of an executive attentional network, which is responsible for regulating the processing of information from other sensory and emotional networks. This is important when performing a task, especially those involving effort or those that are new (non-routine).

Some authors, such as Posner and Botvinick, propose the conflict monitoring hypothesis, which argues that when 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 response planning. and response planning.

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

Emotional control mechanism

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

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

The rostral anterior cingulate cortex can help inhibit the activity of the amygdala, resolving emotional conflicts. This phenomenon is called "emotional top-down".. In patients with depression there is a 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 in the processing of self-referential negative emotional information.

People with Post Traumatic Stress Disorder show hypoactivity of the rostral anterior cingulate cortex when they try to evoke the trauma and during its re-experiencing. In addition, PTSD symptom severity correlates with hypoactivity of the rostral anterior cingulate cortex.

In people with anxiety, there is no suppression of amygdala activity, which correlates negatively with rostral anterior cingulate cortex activity. Changes in this activity will depend on the perceived threat, the degree of helplessness felt by the person and the anticipation of adverse stimuli..

What happens if the cingulate gyrus is injured?

Its lesion produces several disorders and syndromes, such as mutism, imitation behaviors (ecopraxia) and compulsive use of objects.

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

Bilateral cingulate lesions generate sphincter incontinence, tendency to distractibility, docility and fabulation.and to docility and fabulation.

The best known alteration when the cingulate gyrus is lesioned 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 of goal-oriented activities, patients show no interest or concern for anything (neither for their family, nor for themselves or the future).

It would also have to do in the syndrome of dependence on the environment, which entails the loss of personal autonomy (involves a tendency to distraction, hyperreactivity, decreased motivation and apathy).

Bibliographical 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.