According to foreign media reports, have you ever thought about where the voice in your mind comes from when you are silently thinking? Could it be an illusion caused by our memory of speaking?
These questions point to an unsolved mystery, and this mystery is related to our search for “the language that cannot exist”. The so-called “impossible language” refers to the sound in our minds. From a methodological point of view, this mystery is equally important, because in order to solve this mystery, we need to fundamentally change the way we understand the relationship between language and the brain. We need to change from “Which neurons are sending signals” to “Which neurons are sending signals” when the brain is performing language tasks.
Consider a simple question first: What is language made of? There is no doubt that language is composed of words (characters) and combination rules, but in the eyes of physicists, language exists in two different physical spaces: outside the brain and inside the brain. Outside the brain, language is composed of mechanical sound waves formed by densely distributed air molecules (that is, “sound”); inside the brain, language is composed of electric waves that neurons rely on to communicate. In both cases, language is made up of these real things on a physical level.
There is an obvious connection between sound waves and the brain. It is because of sound that the content of one brain can be transmitted to another brain in the form of words. (Of course, the two brains can also exchange language information in other ways, such as eye contact, gestures, braille, etc.) Sound enters the human body through the ears, and then passes through the tympanic membrane, ossicles and snail-shaped cochlea. This complex system can convert the mechanical vibration of acoustic signals into electrical pulses, and decode complex acoustic waves into basic frequencies that can generalize acoustic waves. Then, different frequencies are projected on specific points on the primary auditory cortex, and sound waves are replaced by electric waves.
The pioneering work done by the Nobel Prize winner and electrophysiologist Lord Edgar Adrian has at least taught us that physical signals will not disappear completely after they reach the brain. Scientists have recently discovered an even more shocking phenomenon: in brain areas that are not related to hearing, such as the Broca’s area, which is responsible for speech generation, the brain waves will retain the shape of the corresponding sound waves. .
These findings are of great significance to our understanding of the relationship between sound waves and brain waves. However, these findings almost all rely on a neurophysiological process related to language called “sound emission decoding”. But we know that language can exist without sound, such as when we read (you are doing this right now), and when we think. In professional terms, this is all called “endophasic” (endophasic).
This fact is very simple, but the question it raises is very crucial: What happens to the electric waves in the brain when we form a language expression but do not make a sound?
In 2014, Italian linguist Andrea Moro and his colleagues were determined to find the answer to this question. They compared the shape of electric waves that can describe the activity of the Broca’s area of the brain with the shape of sound waves. The sound waves here include not only the sounds heard by the subjects, but also the sound waves when they read silently in an absolutely quiet environment. In the latter case, the input information has nothing to do with the sound. Of course, analyzing “discourse in the brain” is not a new concept in the field of neuropsychology. But the technique used by Moreau and others to explore this phenomenon is very unusual and instructive, and the results of the research are also surprising.
Awake surgery
Moreau used a method called “awake surgery” in his experiment to collect data. Using this technology, the patient will be awakened after part of the skull is removed to stimulate and analyze the electrophysiological activity of the patient’s cerebral cortex. However, this technology is an invasive method, the brain is a very fragile organ, and patients need to cooperate in situations of extremely fragile emotions. These psychological, technical, and ethical reasons make it difficult to carry out such research.
For example, when a surgeon cuts the cerebral cortex and removes a tumor, he cannot know in advance whether the removal of the brain tissue will interfere with the neural network, so as to destroy or even destroy the cognitive, motor, or sensory functions of the neural network. In order to minimize the damage caused by the operation, after the patient is anesthetized and the skull is opened, the doctor will wake up the patient (a short time, about 10 to 20 minutes), and let the patient do some simple tasks that require the use of the corresponding cortex.
When the patient completes the task, the doctor will use small electrodes to stimulate the patient’s cerebral cortex (this does not cause pain, because the brain has no pain receptors). If the electrical stimulation of a certain part of the cortex will affect the patient’s completion of the task, the doctor can judge that if this part of the cortex is removed, it will cause permanent damage to the patient, and use this to evaluate whether the operation can be performed from another location. The benefits of this kind of surgery to patients cannot be measured by value, and the actual effect is almost beyond the reach of any technology. Not only that, this technology also provides scientists with a unique opportunity to study brain functions and obtain important data.
First of all, doctors can use this to determine the location of the key nodes of the neural network related to specific tasks in any patient’s brain, which solves one of the key problems of neuroimaging technology: the exact location of specific functions in the brain of different subjects may be different Big. In addition, doctors can accurately record neuroelectric activity at the level of a single neuron. However, with existing technology, this level is still difficult to achieve.
In addition to the treatment of local lesions, the application of this technology in other pathological fields is also increasing, such as the treatment of epilepsy that is difficult to treat with drugs. In the treatment of epilepsy, the doctor will first implant electrodes in the patient’s brain, and then close the skull, so that the patient’s information can be continuously provided in the daily environment. With this method, we can further understand the neurophysiological processes that occur in the brain. Compared with neuroimaging technology, this method can provide more accurate and precise spatial information, and can also carry out targeted measurement of brain electrical activity, which is unmatched by any other indirect measurement method.
experiment
In Morrow’s experiment, sixteen patients were asked to read aloud given language expressions, some of which were individual words, and some were complete sentences. Then, the researchers compared the shape of the generated sound waves with the shape of the radio waves in the Broca’s area of the subject’s brain. Unexpectedly, they found a correlation in it.
The second step of the experiment is the most critical: the researchers ask the patients to read these language expressions again, but do not make any sounds, just silently read them in the brain. Then, the researchers again compared the corresponding sound waves with the shape of the waves in the Broca’s area in the patient’s brain. What I want to point out here is that there is indeed a signal entering the brain, but it is not a sound signal, but a light signal carried by electromagnetic waves, or in simple terms, a signal conveyed by the words we use to express words, anyway, it is definitely not sound waves. .
As a result, the researchers were surprised to find that when the subjects read these language expressions silently, the structure of the electric waves recorded in the brain regions that are not related to hearing is exactly the same as the mechanical sound waves produced when these sentences are read . In this way, the two waves of language attachment are closely linked. How close is this connection? Even in the absence of sound, the two waveforms can completely overlap. This shows that the acoustic information of language is not implanted when someone needs to communicate with others, but is part of the language from the beginning, or at least earlier than the sound generation time. In addition, some people previously suspected that when we read or think, the sounds in our minds are nothing more than hallucinations based on our memory of the sounds when we speak. The results of this study have successfully ruled out this possibility.
This finding shows that the role of sound in language processing is much more critical than previously thought. This unexpected association between sound waves and brain waves produced by sound is like the “Rosetta Stone” (Note: The Rosetta Stone was made in 196 BC, with ancient Egyptian, Greek, and other Common texts are engraved with the same content, allowing linguists to interpret the meaning and structure of Egyptian hieroglyphs by comparing different texts, allowing us to use the two known codes to interpret the third code: The radio wave code generated in the case. This in turn may help us crack the unique “fingerprint” of human language.
This discovery also raises many questions. For example, if a person has never heard any sound from birth, what kind of electrical activity will his/her language network (including Broca’s area) produce? Can we use the electrical activity information of the cerebral cortex to understand the sentences in the minds of patients with aphasia, and then hear them “talk” again with the help of artificial voice devices? Can we better understand what we hear in our minds when we are dreaming or when patients are confused? Can we treat severe stuttering as a disorder between different voice representation systems in each neural network, and intervene and treat it? Will these discoveries lead to ethical behavior, against the wishes of others, and forcibly gaining the ideas of others?
The simple fact that most human communication is carried out in the form of waves may not be accidental. After all, waves can carry information from one entity to another without changing the structure or composition of the two entities. Waves can penetrate through our bodies without causing harm to us, but they can also allow us to decipher the information it carries through the instantaneous vibration of the waves. Of course, the premise is that we have a “key” that can “decode”. The word “information” in English is derived from the Latin root “forma”. This is by no means a coincidence. After all, if you want to convey “information”, you must share “shape” with others.
The Austrian philosopher Ludwig Wittgenstein once asked such a question in the book Philosophical Investigations: “Is it possible for people to communicate through their hearts instead of speaking out their words?” With Moreau’s experimental results, Wittgenstein’s highly predictable problem will be viewed from a new perspective. More importantly, many new problems have emerged from this.
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