Precuña: characteristics and functions of this part of the brain

The human brain is a complex and fascinating organ. Each cerebral hemisphere is made up of several lobes.

And in the superior parietal lobe, hidden between layers of nerve fibers, we can find the precuña, a region unique for its characteristics and functions that have been assigned as the main center of cerebral coordination, as well as for participating in the processes. of self-awareness.

In this article we tell you what precuña is, What is its structure and where is it located, what are its main functions and what role does it play in the development of Alzheimer’s disease.

    Precuña: definition, structure and location

    The precuña or precúneo is an area in the superior parietal lobe, hidden in the longitudinal slit of the brain, Between the two hemispheres. It borders at the front with the marginal branch of the cingulate groove, at the rear with the parietooccipital groove and, below, with the subparietal groove.

    Sometimes the forehead has also been described as the medial area of ​​the superior parietal cortex. In cytoarchitectural terms, corresponds to Brodmann zone 7, A subdivision of the parietal region of the cortex.

    In addition, it has a complex cortical organization in the form of columns and is one of the brain regions that later complete their myelination (the process by which axons are coated with myelin to, among other things, improve the speed of transmission of nerve impulses. ). Its morphology exhibits individual variations, both in shape and longitudinal size.

    Likewise, la precuña has many neural connections; at the cortical level, it connects to sensory-motor areas, areas related to executive functions, memory and motor planning, and the primary visual cortex; and at the subcortical level, it has important connections with the thalamic nuclei and the brainstem.

    The precuña is a structure that has developed more in humans than in animals, because at the evolutionary level there has been a considerable increase in the size (in shape and surface) of the parietal and frontal lobes of the cortex. human brain by respecting the rest of the animal kingdom, with all that this implies with regard to the development of higher cognitive functions. It is therefore, a structure that has aroused great interest in the neuroscientific community, Despite being anatomically so “elusive” (due to its location).

      functions

      The precuña is one of the main areas of regulation and integration of our brain, And acts as a kind of conductor through which pass many signals necessary for this organ to function as an integrated whole.

      Then, the different functions attributed to the precuña are exposed:

      Autobiographical information (episodic memory)

      The forehead works in relation to the left prefrontal cortex, involved in processes related to episodic memory and autobiographical memories. In this sense, it participates in aspects such as attention, the recovery of episodic memory, working memory or the processes of conscious perception.

      1. Visuospatial processing

      Another of the key functions in which it has been suggested that the precuña is involved is the visuospatial processing; this area would participate in the management of spatial attention, when there is movement and, also, when images are generated.

      It is also believed to be responsible for motor coordination in divided care processes; that is, when it is necessary to shift attention to different places or spatial locations (for example when writing text or drawing a table). In addition, the precuña would be activated, along with the premotor cortex, in mental operations that require visuospatial treatment.

      2. Self-knowledge

      Several investigations have linked the precuña to processes in which the consciousness of self participates; in this sense, this cerebral region would play a relevant role in the integration of the perception of ourselves, in a network of spatial, temporal and social relations. The forehead would be responsible for generating this feeling of continuity between the brain, the body and the environment.

      In studies with functional images, it was observed that this brain structure analyzes and interprets the “intention” of others in relation to ourselves; that is, it would act as a mechanism to analyze the judgments of others that require appropriate interpretation in order to act in agreement (eg, with empathy).

      3. Conscious perception

      In addition to having a relevant role in the processes of self-awareness, it has been suggested that the precuña could be, along with the posterior cingulate cortex, relevant to the processing and conscious perception of information.

      It was observed that upon awakening, the metabolism of glucose in the brain increases significantly, unlike what happens under the influence of anesthesia. In addition, during slow wave sleep and fast eye movement sleep or REM sleep, the precuña would be practically deactivated.

      On the other hand, it is believed that cognitive functions related to this brain region could help integrate internal information (which comes from the brain and our body) with environmental or external information; in this way, the precuña would play an essential role in the processes that generate brings back to consciousness and the spirit in general.

      4. Core of the integrator

      There are more and more studies that support the role of the precuña as neural network integration center brain, for its high centrality to the cortical network of this organ and its many and powerful connections with the prefrontal areas in charge of executive functions such as planning, supervision and decision-making.

      Pregnancy in Alzheimer’s disease

      Alzheimer’s disease, in its early stages, it begins with metabolic problems in the region of the medial parietal lobes. It appears that the enlargement of these brain regions is what confers some vulnerability to the subsequent neurodegeneration experienced by these patients.

      Several studies have suggested that there may be a relationship between pregnancy and the development of this serious disease. As mentioned above, the precuña evolved differently in humans than in animals: the main difference compared to other primates, for example, is that this structure has particularly high metabolic levels.

      Apparently, the precuña has higher levels of metabolic expenditure than those that would correspond to its size, What also happens with its thermal values. The funny thing is that Alzheimer’s disease begins with metabolic problems in the deep medial parietal region, where the wrist is located. And a hallmark of Alzheimer’s disease is tau protein phosphorylation, which occurs in overwintering mammals in response to changes in temperature.

      What neuroscientists suggest is that a condition as common and characteristic of humans as Alzheimer’s disease is associated with areas of the brain that have a specific morphology in humans. And what is questioned is whether the increased complexity of these brain areas could have led to an increase, also, in biological complexity which, in turn, could lead to an increased metabolic load. , oxidative stress and problems. predispose a person to Alzheimer’s disease.

      However, the possible link between the precuña and other similar structures with the development of this disease and other neurodegenerative diseases is currently being studied, with the aim of finding new drugs and therapeutic targets that cure or at least slow their progress.

      Bibliographical references:

      • Cavanna, AE and Trimble, MR (2006). The precuned: a review of their functional anatomy and their behavioral correlates. Brain, 129 (3), pages 564-583.
      • Miners, JS, Palmer, JC and Love, S. (2016). Pathophysiology of precuneal hypoperfusion at the onset of Alzheimer’s disease. Brain Pathology, 26 (4), pages 533-541.

      Leave a Comment