The cingulate gyrus, also known as cingulate gyrus, cingulate convolution , cingulum or 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 arched-shaped convolution, close to the surface of the corpus callosum.
In simplistic terms, the cingulate gyrus is like a “passing” structure, like a bridge, which differentiates us greatly from animals that have evolved differently from us.
It connects the structures that put us on an equal footing with other animals (the limbic system: let us remember the importance of the hippocampus and the amygdala) and those that give us the ability to plan, reason, and perform 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, dorsomedial nucleus of the thalamus, inferior parietal lobe, lateral convexity and medial frontal lobes.
- It plays a connecting role between the volitional, cognitive motor, emotional and mnestic aspects.
- It deals with modulating and processing the expression of subtle emotional nuances
- It intervenes in the modulation of the voice (sadness, happiness).
- It takes care of learning emotional vocalization, which facilitates the formation of long-term attachments, especially mother-child attachment.
- Their stimulation produces feelings of anxiety, pleasure and fear.
- It is in charge of initiating the behavior oriented to significant motivational goals for the subject.
- The subcallus region is responsible for the regulation of autonomic functions such as breathing and heart rate.
- It participates 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 the selective attention involved in the correct resolution of the Stroop test and in other motivational-driven attentional tasks. The role would be to monitor the conflict between stimulus and response to select appropriate behavior.
- It plays an important role related to motivation in the functioning of the pre-frontal cortex for voluntary actions.
The Papez circuit
Papez (1929) stated that the communication between the hippocampus and the neocortex takes place in a reciprocal way .
They are constantly connected by means of the cingulate gyrus, and it would be carried out in the following way: the hippocampal formation processes the information coming from the cingulate gyrus, and takes it to the mammillary bodies of the hypothalamus (through the phornix).
At the same time, the hypothalamus sends information to the cingulate gyrus via the anterior thalamic nucleus-mamillary bodies and from there to the frontal cortex.
Posner and other authors (2007) have stated that the above cingulate turn is part of an executive attentional network, which is in charge of regulating the information processing of other sensorial and emotional networks. This is important in order to perform a task, especially those that involve effort or are new (non-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 previous cingulate turn puts into action a set of strategic adjustments in cognitive control and in response planning.
Their aim is to reduce conflict in the task and, on the next occasion, to get it right. It is like a controlled mechanized evaluation of the results. If these are not satisfactory, information is sent to other structures in the planning system (frontoparietal and cerebellum system) which are responsible for establishing strategies for action and learning from the mistake.
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, we simultaneously experience an increase in heart rate, dry mouth, tense muscles, and so on.
The anterior rostral cingulate cortex can help inhibit the activity of the amygdala, resolve emotional conflicts. This phenomenon is called “emotional top-down” .
In patients with depression there is an overactivation of the anterior cingulate cortex in the processing of self-referential negative words. More specifically, there is a positive correlation between the amygdala, the medial prefrontal cortex and the rostral cingulate cortex in the processing of negative self-referential emotional information.
People with Post-Traumatic Stress Disorder, show hypoactivity of the anterior rostral cingulate cortex when trying to evoke the trauma and during their re-experimentation. In addition, the severity of PTSD symptoms correlates with the hypoactivity of the anterior rostral cingulate cortex.
In people with anxiety, there is no suppression of the activity of the amygdala, which correlates negatively with the activity of the rostral anterior cingulate cortex. The changes in this activity will depend on the perceived threat, the degree of defenselessness felt by the person and the anticipation of the adverse stimuli .
What happens if the cingulate gyrus is injured?
Their injury produces several disorders and syndromes, such as mutism, imitative behavior (ecopraxy), 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 incontinence of sphincters, tendency to distractibility , docility and fable.
The best known alteration when the cingulate gyrus is injured is the frontal medial 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 show no interest or concern for anything (neither for their family, themselves nor the future).
It would also have to do with the environment dependency syndrome, which leads to the loss of personal autonomy (it involves a tendency to distraction, hyperreactivity, decreased motivation and apathy).
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