Left cerebral hemisphere: parts, features and functions

The idea that the cerebral hemispheres differ from each other is quite accepted, both in general culture and in more academic contexts.

It is often said that the left hemisphere is what lies behind logical and analytical fields, like mathematics, while the artistic is related to the right hemisphere. It is also assumed that the right hemisphere controls the left side of the body, while the left does the same but with the right side.

Let’s go further in the left cerebral hemisphere, What characteristics are assigned to him and in what functions he is involved.

    What is a cerebral hemisphere?

    Before talking in depth about the left hemisphere, we will first define that it is a cerebral hemisphere. A hemisphere, from the Greek “hemi” (“half”) and “Sphera” (“sphere”), is each of the two main structures that make up the brain. Each hemisphere represents one of the two halves of the brain, One on the right and one on the left.

    These hemispheres are inverses of each other, but are not symmetrical. The line between them is called the interhemispheric or longitudinal slit of the brain, and in the deepest part is a structure, called the corpus callosum, which connects the two hemispheres.

    How is the left hemisphere of the brain structured?

    Like its right-wing counterpart, the left hemisphere is anatomically structured into lobes, Having half of each. These lobes are the frontal, parietal, temporal, occipital and insula lobes.

    As we have already mentioned, the corpus callosum, which is a nerve fiber structure, connects the two hemispheres to allow them to communicate. As for the other hemisphere, the left is protected by the following layers:

    • Duramadre: It is the outermost membrane and the closest to the skull.
    • Arachnoids: It is between duramater and piamater.
    • Piamadre: It is the innermost membrane. It is contiguous with brain matter.

    main Features

    Anatomically, the two hemispheres are very similar. Although, as we have already mentioned, they are not symmetrical, they are very similar. They have both cracks and convolutions and both have the same number of lobes, in addition to being a similar size.

    However, they have different attributes. The left hemisphere is known to be the brain structure in charge more of the linguistic aspects, in addition to being behind the analytical processing, Specific to mathematics. Let’s take a closer look at these features:

    1. Symbolic

    The left hemisphere is the person in charge of using the symbols for the representation of concepts as well as objects.

    It is therefore this hemisphere that makes it possible to understand that the symbol “+” means adding to something or more quantity, or that the symbol ☮️ means peace.

    2. Verbal

    As we have already mentioned, the left hemisphere is this is involved in the use of verbalized language.

    This means that it is what lies behind everyday and fundamental aspects of human communication such as speaking, verbal memory, writing and reading.

    3. Analytics

    When we say that this hemisphere is analytical, we come to indicate that its information processing is done by following successive steps in a more or less linear way, Analyze each of the details of a given situation or problem.

    This is why the left hemisphere is so important in mathematics, in which, in order to arrive at a solution, it is necessary to identify the steps to follow in order to have the correct answer.

    Outraged, it is detailed and relatively objective when it comes to analyzing reality, Allow to make specific observations and raise a concrete reflection, adapted to the problematic situation.

    4. Temporal

    It follows the passage of time, that is to say order things in temporal sequences. It goes from start to finish.

    5. Rational

    The left cerebral hemisphere tends to potentiate rational reasoning. In other words, that is to say it allows to abstract an explanation of the reality of reason.

    6. Logical and linear

    When we say that the left hemisphere makes sense, it means that it establishes causal relationships between different facts. Thus, a phenomenon must necessarily be caused by a precedent or be responsible for a subsequent consequence.

    This characteristic, as well as the analytical aspect of this hemisphere, acquires great importance in the resolution of mathematical problems.

    As for the linear aspect, he has just indicated that ideas are always chained.

    the functions

    These are the main functions of the left cerebral hemisphere.

    Verbal language and mathematics

    Related to both verbal and symbolic ability, the left hemisphere is able to identify groups of letters and interpret them as words which, in turn, form groups of them and form sentences with meaning.

    Thanks to this, it also plays an important role in speech, writing, math problem solving, numbering and logic.

    Other aspects in which this hemisphere is remarkably involved are verbal memory, grammar, syntactic organization, phonetic discrimination, planning, decision-making, long-term memory …

      Expression and understanding

      John Hughlins Jackson, a neurologist, said at the time that the left hemisphere was the center of the faculty of expression. This means that this hemisphere is responsible for transforming a body of information into something meaningful.

      like that, this hemisphere stores concepts which will then be emitted in the form of words, Both orally and in writing, allowing ideas to be transmitted from within the mind of one person to another through the use of verbal communication.

      With embolism affecting this hemisphere, functional losses such as loss of speech may occur, as well as impaired motor skills on the right side of the body, as the left hemisphere controls this half of the body.

      Relationship between the two halves of the brain

      Although we have pointed out that each hemisphere has its own peculiarities and functions, this does not mean that they are radically different from each other or that they do not perform activities together. What must be understood is that there are activities carried out mainly by one of the two hemispheres and others in which it is the task of their counterpart.

      Out of curiosity, research points out that interhemispheric differences are somewhat distinctive of the human species. In most people, the two hemispheres complement each other. Verbal aspects such as speech are usually under the control of the left hemisphere, however, there are cases, especially in left-handed people, in which speech is an activity performed by areas located in both hemispheres.

      In addition, we have seen that, in situations where brain injury occurs, there may be changes in the location of certain functions. This “ transfer ” of functions is particularly important in childhood, when, thanks to brain plasticity, the brain tries to “ save ” a capacity from the injured area by making it another area, and perhaps to the hemisphere. on the contrary, which supports.

      Bibliographical references:

      • Acosta MT (2000). Right hemisphere syndrome in children: functional correlation and maturation of nonverbal learning disabilities. Rev Neurol; 31: 360-7.
      • Anderson, B .; Rutledge, V. (1996). Effects of age and hemisphere on dendritic structure. Brain. 119: 1983-1990.
      • Hutsler, J .; Galuske, RAW (2003). Hemispherical asymmetries in the cerebral cortical networks. Trends in neuroscience. 26 (8): 429-435.

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