The precuneus is a subarea in the cerebrum. It is located at the level of the back of the head, directly under the skullcap. Together with the hippocampus, it performs tasks in the learning process.
What is the precuneus?
The precuneus is a part of the central nervous system. It is located in the cerebrum, the telencephalon. In a medial view of the brain, it is visible in the upper last third of the cerebrum. It is clearly visible between the transition of the praecentral gyrus to the postcentral gyrus and the parietooccipital sulcus. It is assigned to the gray matter of the cerebrum. This represents an essential component of the central nervous system. It contains nerve cell bodies, dendrites, axons, and glial cells and capillaries. Research has shown that the precuneus, together with the hippocampus, performs important functions in learning. For example, it is thought to be involved in the formation of self-image and episodic memory. The precuneus becomes active in various imaging studies, such as magnetic resonance imaging, whenever the perception of the self is involved. For this reason, the precuneus plays an essential role in the study of the conscious state of mind. Although research in this area is still ongoing, scientists are certain that the precuneus forms its own memory representation.
Anatomy and structure
The cerebrum is divided into several areas. They include the frontal lobes, the parietal lobes, the temporal lobes, and the cingulate gyrus. Together, they encase the bar, the hippocampus, and the limbic system. The sulcus centralis wraps around the lobulus paracentralis and ends above the gyrus cinguli, The lobulus paracentralis forms the transition from the gyrus precentralis to the gyrus postcentralis. Further back is the sulcus parietooccipitalis. This separates the parietal from the occipital lobes. Nearly perpendicular to it runs the sulcus calcarinus. The primary visual cortex is located in its walls. The sulcus parietooccipitalis and the sulcus calcarinus delimit the structure of the cuneus. This is wedge-shaped. Rostral to the parietooccipital sulcus is the precuneus. Thus, the precuneus is located between the lobulus paracentralis and the sulcus parietooccipitalis. From a neurophysiological point of view, the precuneus is often described as part of the lobulus parietalis superior. This is a subarea of the partietal lobe and is referred to as the cortically sensitive accessory field. The tissue of the precineus corresponds to that of the rest of the cerebrum. It is referred to as gray matter, which consists of neurons, glial cells, as well as myelinated fibers.
Function and tasks
The precineus is thought to have tasks such as self-awareness, self-reflection, and awareness of self. In everyday life, processes that result in self-assessment occur in this area of the brain. In the precuneus, it is decided whether the person feels up to coping with a task or rejects it. This requires elements of long-term memory, accumulated experience, and an assessment of the current situation. Self- or self-awareness is a very complex process. Together with self-observation for one’s own awareness and self-confidence, they represent important areas in coping with everyday situations. The correct assessment of present challenges, emotions for coping, such as courage, endurance or strength, as well as the examination of available resources are weighed in a few seconds or minutes. This process is controlled to a large extent from the precuneus. In cooperation with the hippocampus, processes of learning take place in this brain area. Long-term memories are formed in the hippocampus. Long-term potentiation takes place there. This lasts several days to months. Once a memory is stored in the declarative memory, it can be retrieved for a lifetime. This includes factual knowledge, but also knowledge about action sequences. The latter plays an important role in self-assessment. Only by knowing how actions proceed and what possibilities one’s own organism produces can a new action be planned and successfully implemented.
Diseases
Lesions in the brain can result from various diseases, such as inflammation, circulatory disorders, or tumors. In addition, damage can be caused by accidents, falls, or as a result of surgical procedures.Brain swelling causes pressure in the brain. The swelling cannot escape due to the predetermined shape of the skull. The affected brain mass displaces healthy areas. These become trapped and can no longer perform their tasks adequately. Hemorrhages with central nervous consequences may occur. Lesions and impaired functional activity in the precuneus lead to problems in the process of learning. Learning processes cannot be completed successfully. This leads to reduced self-assessment. Precuneus failures are associated with disorders in which a disturbance in self-perception is indicated. Therefore, disorders such as borderline personality disorder or the eating disorder anorexia nervosa are associated with functional impairment of the precuneus. In both disorders, patients suffer from a faulty self-image. Borderline personality disorder is also called emotionally unstable personality disorder. It is associated with impulsivity and instability of emotions and mood. The disorder exhibits problems with one’s identity and brings immense problems in interpersonal relationships. In Anorexia Nervosa, patients suffer from the body schema disorder. Even with objective facts, they cannot perceive what body image they have. They themselves see their body as fat or even fat, even if they suffer from very severe underweight.
