Speech and functional brain asymmetry

Already at the end of the 19th century, the idea of ​​functional asymmetry of the human brain became a scientific truism. It was established that the left hemisphere is responsible for sign, rational-logical speech, primarily thinking, and the right one - directs the orientation of a person in space, his thinking is primarily emotional, figurative, and intuitive. Scientists have also found that because of the innate properties of different people, one of the hemispheres “works” as it were better than the other. What we all share is left handed (those who do well with speech (especially written), but not so well oriented in space) and right handed people (those who, as a rule, have good artistic abilities, but have great difficulties with written speech). There is, however, another transitional type - ambolars, whose hemispheres are equally developed.

As we have said, for a long time the opinion prevailed in neurolinguistics that the left hemisphere of the brain is dominant (i.e. the main, thought-speech), and the right hemisphere is subdominant, subordinate to the left. However, such judgments were hasty. Gradually it became clear that a) only the majority of right-handers (not one hundred percent) speech zone is localized in the left hemisphere, and the majority of left-handers (although not one hundred percent) it is localized in the right hemisphere; b) in case of operative medical intervention, in which both halves of the brain were cut along (along the so-called “corpus callosum”), thus losing the ability to interact, both halves assumed functions not characteristic of them: understanding speech, solving verbal and non-verbal tasks , the formation of in connection with them emotional assessments. This was confirmed by interviewing patients who underwent such an operation in a state of divided brain.

Studies of the last two decades have changed the established understanding of the role of the right hemisphere in human speech. The answer to the question about the nature of the participation of each of the cerebral hemispheres in speech activity was obtained in the treatment of various serious diseases (especially epilepsy) using unilateral electroconvulsive shock. The task of such treatment is to cause the patient something like a series

fainting, which usually improves his condition. To do this, electrodes are attached to a person's head and a current is switched on for a moment. A gentle treatment procedure is that the electrodes are connected to only one half of the head. In this case, only one hemisphere is suppressed, the second continues to work normally.

This creates a unique situation where the same person can be observed in three states: before the session (he has both hemispheres), with the right hemisphere oppressed and with the left hemisphere oppressed. There was an opportunity to check the degree of participation of different hemispheres in the production and perception of speech. Domestic neurolinguists L. Ya. Balonov, VD Deglin, and others. A series of experiments was developed and carried out, some of the results of which will be given below.

1. The task to perform the drawing of an object .

When oppressing the right hemisphere, the subjects often refused to complete the task, citing the fact that they could not “imagine” the object that had to be drawn. In this case, instead of portraying the object, they often wrote the word denoting this object. When oppressing the left hemisphere, the participants in the experiments never abandoned drawing, drew even more readily than in control studies (where both hemispheres “worked” for them), did not replace the image of the object with its name and did not make explanatory inscriptions.

Next, consider the relationship of each of the hemispheres to the various units of language and speech.

2. The sound aspect of the language . When the left hemisphere is “turned off”, the subjects largely lose the ability to distinguish phonemes. They hardly distinguish words in a speech flow. However, they perfectly capture intonation, they clearly distinguish the timbre of speech (and can distinguish a woman's speech from a man's speech). Listening to songs, they poorly understand the words, but they well perceive and reproduce the melody. When oppressing the right hemisphere, patients distinguish words in the utterance, but they are completely unable to determine the intonation, to distinguish the woman’s speech from the man’s speech, to reproduce the melody of the song.

3. The lexical composition of the language . In the case when the left hemisphere is “turned off”, the stock of the subject’s active vocabulary is sharply reduced. It begins to dominate the form of clichés (greetings, apologies, various kinds of ritualized verbal signs), interdental education, curses. When conducting associative experiments, patients produce few adjectives, verbs, abstract nouns, and service parts of speech. They have difficulty understanding words with an abstract meaning (religion, malice, concern, fear, etc.).

With the oppression of the right hemisphere, the number of active vocabulary increases dramatically, abstract nouns appear in associations. In the associative experiment, there is a plurality of language and even talkativeness.

4. Perception of idiomatic expressions and metaphors . A simple experiment was conducted. The subjects were offered combinations of three cards with the words: a) climb into the bottle, b) climb into the window, c) get angry; a) steel nerves, b) steel rails, c) a strong person, i.e. a) a metaphor or idiom, b) similar to the previous phrase without a metaphorical meaning, c) the meaning of the first expression. The patient had to put together the cards with the phrases that, in his opinion, fit each other. When the left hemisphere is “turned off”, patients, as a rule, put together to climb into a bottle and get angry; nerves of steel and strong man.

When the right hemisphere was depressed, most of the subjects united to crawl into a bottle and crawl through a window; steel nerves and steel rails. In other words, the direct meaning of words is perceived mainly by the left hemisphere, figurative - by the right one.

5. Perception of syntactic constructions . The subjects were asked to sort the sentences like “Vanya beat Petya”, “Vanya beat Petya”, “Petya beat Vanya”, “Petya beat Vanya”, etc. With the right hemisphere turned off, the sentences were clearly grouped depending on who in the proposal is the subject, and who - the object. In one group, “Peter beat Vanya”, “Vanya beat Petya”, “Vanya beat Peter” were in), and in another group there were sentences in which Vanya was the actor.

When the left hemisphere was depressed, the behavior strategy of the patients was fundamentally different: in one group there were combined sentences that began with the words of Petya, into another group - with the words of Vanya.

Based on this, it can be assumed that the left hemisphere is responsible for the delicate mechanism of verbal transmission of subject-object relations. The right hemisphere is based on a more generalized principle of syntax: at first there is what is at stake (the reader remembers that in science it is called the word “Theme”), and then what is said about it (“Rem”).

6. The perception of the text . The participants in the experiments were given a task to retell the text (the experiment used the story “Two Comrades” by L. Tolstoy). With the “off” left hemisphere, the retellings were generally less than with “off the right”, but the set of keywords was more. In other words, the right hemisphere is characterized by an orientation towards a holistic sense, while the left hemisphere is more responsible for the fullness of its verbal realization.

Based on the analysis of the above facts, L. V. Sakharny concluded that there are two grammars in our brain - left-hemispheric and right-hemispheric . Each hemisphere provides its own strategy in the management of speech activity. The main difference is that the left hemisphere is responsible for abstract-logical analysis of the information received. These mechanisms are described in traditional grammar textbooks. Operations of the left hemisphere are associated with the selection of the text of sentences, words in sentences, with the identification of links between words and sentences of the text, with the choice of the most accurate name of the concept, with the control of the sound word matching, etc.

The right hemisphere processes information based on the subconscious; his activity is connected with a concrete, but also global mastering of the situation of communication. According to Sugar, hemispherical grammar operates with ready-made cliché sentences, complete texts, highlighting in their structure subject-rhematic segmentation of phrases.

Considering in the light of the theory of interaction of the cerebral hemispheres, the processes of generation and understanding of speech, we can fill with the neuro-linguistic content described in the third chapter of the model. To begin with, different communicative

conditions require different efforts from different hemispheres. Domestic conversational communication, based on the common situation and widely used speech stereotypes can be associated only with the right hemisphere with minimal participation of the left. More complex forms of speech activity involve jointly coordinated work of both hemispheres. So, obviously, the primary stage of motivation, the formation of communicative intentions and design (in the figurative code of the CPC) is carried out in the right hemisphere. It is there that the idea of ​​the goal and the general idea of ​​the future statement appears, when the speaker knows what he will say, but does not know how.

Then in the left hemisphere the transcoding of the message content in the internal speech takes place. It is here that under the guidance of the speech zones of the left hemisphere, the choice of syntactic schemes and predicates takes place. Only then these schemes are filled with vocabulary, the selection of grammatical attire for which occurs under the guidance of the hind-hemispheric (“knowing”) divisions of the left hemisphere. The process of “dressing up” thoughts into words takes place under the vigilant control of the right hemisphere, which constantly compares the results with the original plan and reality.

Even more difficult is the neuro-linguistic picture of understanding speech. Both hemispheres here begin to work from the first word. The left hemisphere performs "decoding" of language signs, which, as the reader remembers, occurs in the posterior regions of the left hemisphere. In parallel with the activity of the left hemisphere in the right hemisphere, there is an active search for a holistic sense of the perceived message, anticipating the completion of decryption (anticipation). In addition, the right hemisphere helps the left in understanding various kinds of portable meanings of words, clichéd winged expressions, etc. The results of the analysis of the left hemisphere are transferred to the right, and here they are compared with the data of intuitive sense comprehension, based on the analysis of intonation, nonverbal and visual accompanying communications, etc. Then the revealed content is checked for “common sense” by correlating analysis data with facts of reality. If the ratio does not suit the listener, then the information is again transferred to the left hemisphere, where it is subjected to additional analysis, etc.

Of course, the presented model - only in a rough approximation reflects the most complex processes that occur in our brain during speech activity. Further searches for neurolinguists will make them refined and modified. One thing is obvious: the normal brain functions successfully only in the interaction of both hemispheres. Therefore, it is hardly true that one of them is completely dominant.

At the same time, it remains indisputable that visual-figurative thinking is the basis of intellectual activity at a fundamental level. This level is most of all connected with the “right brain”, which by itself does not need speech and without it correctly assesses the visual situation, knowing what it is with “what” that “it” is and is able to faithfully on “it” to react. However, this level is unknown, as "it" is called. Without the help of the left hemisphere, the “right brain” is not able to form any complete statement (message) about the object of thought.