Arched fascicle of the brain: location and functions

Speaking is one of the abilities or skills that have traditionally been most valued. And although most people use it automatically and even without thinking about what they are saying, the truth is that speaking involves a number of complex processes.

These processes are carried out by different areas of the brain. One of the main ones, next to the Broca and Wernicke districts, is the curved booklet.

    Archived file: what is it and where is it?

    By curved fascicle is meant a specific brain region made up of a set of nerve fibers that connects two of the main areas related to language: the Broca and Wernicke areas. In this sense, it is necessary to emphasize that the connection is bidirectional: the fibers go from the region of Wernicke to the region of Broca but also backwards.

    This bundle thus connects the frontal and temporal areas, as well as the parietal and perisilvic areas. In other words, it connects the motor areas and the sensory areas. These connections are made of white matter: that is, the arched fascicle is made up mostly of neural axons, and it is not so common to find neural nuclei. They are usually short, arched neurons (hence their name).

    These fibers are found in both cerebral hemispheres, While what was most relevant in the study is that of the dominant hemisphere of the tongue (in most people, the left).

    main duties

    This small region of the brain plays a very important role in our behavior, especially when it comes to language. Interestingly, while the role of this fascicle in the dominant hemisphere for language has been widely analyzed, the existing knowledge about its function in the other hemisphere is not fully understood. Generally speaking, we can say that some of the main functions of the curved fascicle are as follows.

    1. Sound information

    Different studies seem to reflect the role of the arched bundle in language it is not given at the level of meaning, but only at the level of sounds. In other words, what is transmitted is not the meaning, which must not have been processed at a conscious level, but the phonemes.

    2. Connection between Broca and Wernicke

    As discussed above, the arched bundle is a bundle of fibers that join the Broca and Wernicke areas. In other words, it brings together the main areas of the brain responsible for the production and understanding of language. even if his injury prevents him from understanding or producing language, The curved booklet is important to link these two processes.

    3. The ability to repeat

    One of the most visible characteristics of this area (since its injury prevents it) is the ability to repeat words. In other words, the curved fascicle it allows us to be able to repeat what another person tells usSomething largely related to the previous point. This aspect makes sense if we consider that the booklet connects the Wernicke area with the drill. That is to say: we first understand what we are told and then we reproduce it.

      4. Word learning

      Also, another of the functions in which the curved fascicle is involved is word learning. Largely related to its role in repetition ability, it has been observed by magnetic resonance imaging as people who have better verbal learning have a higher level of myelination of the arcuate bundle.

      This implies that the nerve signal descended more quickly through the fascicle, and you can probably find a connection with its association with the ability to repeat the words we are told.

      5. Prosody, semantics and phoneme-morpheme transformation

      It has been observed in several studies that semantics and prosody are also influenced by this brain structure. It also contributes to the process of transformation of phonemes (Sounds) in morphemes (already significant) although the information passing through it is fundamentally phonetic.

      6. Musical perception

      One of the few functions that the straight arched fascicle has been linked to is related to musical perception. And it seems that the operation of the upper part of the curved fascicle of this hemisphere this allows us to capture the different tones of a melody.

      7. Drafting

      We have seen that the curved booklet influences not only oral but also written language, in particular in tasks where it is necessary to switch from spoken to written material such as in dictations.

      Effects of his injury

      Being the arched fascicle relevant to human beings, the truth is that his injury does not prevent the reception and understanding of the language or its expression. However, this can cause great difficulty.

      And if understanding and expression are preserved, their joint action is cut off if there is an injury to the arched fascicle. Damage to this brain region has also been shown to cause conduction aphasia, in which this makes it impossible or greatly hinders the ability to repeat words. And not just orally: the arched packet injury also makes it difficult to perform tasks like dictations, exhibiting some level of spelling and sometimes not knowing how to correct misspelled words when they know they are wrong.

      We have also seen that there can be a link with the perception of tones, and can lead to deafness and difficulties of musical perception.

      Bibliographical references:

      • López Barroso, D .; Catani, M .; Ripollès, P .; Dell’Acqua, F .; Rodríguez Fornells, A .; By Diego Balaguer, R. (2013). Word learning is mediated by the left arched fascicle. Proceedings of the National Academy of Sciences.

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