There is one obvious connection between sound waves and the brain. Sound is what allows the contents of one brain, as expressed in words, to enter another brain. There are, of course, other ways for two brains to exchange linguistic information — through the eyes, via sign language, or through tactile systems such as Braille or the Tadoma Method , for example.
Sound enters us through our ears, traveling across the tympanic membrane, the three tiniest bones in our body known as the ossicles, and the Corti organ in the cochlea — a snail-shaped organ that plays a crucial role in this process.
The different frequencies are then mapped onto dedicated slots in the primary auditory cortex, at which point the sound waves are replaced by electric waves. Not all linguistic communication uses soundwaves to communicate — braille relies upon the sense of touch Credit: Alamy.
At least since the pioneering work of Nobel Prize-winning electrophysiologist Lord Edgar Adrian we have known that no physical signal is ever completely lost when it reaches the brain.
These findings shed important light on the relationship between sound waves and electric waves in the brain, but almost all of them rely on one aspect of the neuropsychological processes related to language: namely, sound emission decoding. Yet we know that language can also be present in the absence of sound, when we read just as most of you are probably experiencing at this very moment or when we use words while thinking — in technical terms, when we engage in endophasic activity.
This simple fact immediately raises the following crucial question: what happens to the electric waves in our brain when we generate a linguistic expression without emitting any sound?
In , my colleagues and I set out in search of answers. But the technique we used to explore this phenomenon was unusual and illuminating, and the results were unexpected, to say the least. In our experiment , data were collected by means of so-called awake surgery. This technique offers the possibility of stimulating and analysing the electrophysiological cortical activity of patients who have been awakened after a portion of their skullcap was removed.
The invasive nature of this technique, the fragility of the organ involved, and the cooperation of patients in an extremely delicate emotional state make this research very difficult for obvious psychological, technical, and ethical reasons. The surgeon who cuts the cerebral cortex to remove a tumour, for example, cannot know in advance except in specific cases whether cutting the cerebral tissue will interrupt a neuronal network and thus impair or destroy a cognitive, motor, or perceptual capacity that is supported or conveyed by that network.
To minimise any potential damage from the surgery, then, once the patient has been anaesthetised and a portion of the skullcap has been removed to access the surgical site, the surgeon wakes the patient for a short transitional period of about 10 to 20 minutes and asks him or her to perform some simple tasks that should require their utilising the exposed cortex.
If the electrical stimulation in a certain portion of the cortex interferes with the performance of a given task, the surgeon knows that cutting that fragment of cortex could permanently damage the patient and can evaluate whether an alternative surgical site is available.
Stimulating the brain during "awake surgery" has allowed surgeons to determine the function of different networks of neurons Credit: Alamy.
The patient gains an invaluable advantage from these exercises, and one that is practically impossible to obtain through any other technique.
At the same time, this technique provides us with a unique opportunity to investigate brain functioning and obtain extremely important data. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights.
Measure content performance. Develop and improve products. List of Partners vendors. Thought broadcasting is a condition that causes a person to believe that their thoughts can be heard or known by people around them.
Some people believe that their thoughts are being broadcasted by the television, radio, or the internet and in some cases might avoid interacting with these mediums. Thought broadcasting is usually a symptom of a psychotic disorder like schizophrenia and bipolar disorder.
Thought broadcasting is primarily characterized by an unshakeable feeling that people around you can hear your innermost thoughts. In most cases, people who experience this phenomenon are in a constant state of distress because they think that people can hear their thoughts.
For example, imagine you are waiting in line for a coffee and a person cuts the line. You might think to yourself that this was impolite and perhaps call the person a rude word in your mind. A person dealing with thought broadcasting will be plagued with the thought that everyone on the line had heard the rude word they had only thought about.
They might even become so overwhelmed by this belief and leave the coffee shop. Thought broadcasting occurs in different ways for different people. For some people, they might hear their thoughts being spoken aloud, when they are not actually saying them out loud. Others might feel like their thoughts are silently escaping them and as a result, might be heard by the people around them. Some people with this condition might even think that people around them can somehow read or participate in their thoughts.
Other people with this condition have also reported trying to communicate with their thoughts or sending telepathic prompts to other people with their minds.
When they get no response it might sometimes cause feelings of frustration, anger, and sadness. People with thought broadcasting also tend to become socially withdrawn for fear of being ostracized by the people around them because of their thoughts.
They may isolate themselves to prevent others from hearing these thoughts. Thought broadcasting is usually indicative of an underlying psychotic condition. It may be difficult to diagnose as people who experience thought broadcasting often have a difficult time talking about it. They often fear that they might be ridiculed or mocked because of the condition.
As it is one of the symptoms of medical conditions like schizophrenia and bipolar disorder, thought broadcasting might occur with other common symptoms of these conditions, such as:. Thought broadcasting is typically a symptom of a psychotic disorder like schizophrenia or bipolar disorder. Distorted Sense of Reality. People with schizophrenia have an altered perception of reality.
Symptoms of schizophrenia could either be positive or negative:. Schizophrenia is characterized by delusions, or fixed false beliefs, and thought broadcasting is one of these delusions. A team of scientists in America have been able to recreate audible words that volunteers have only imagined by decoding the electrical activity in their brains.
The researchers, from the University of California, Berkeley, say they may one day be able to use their discovery to hear people's thoughts.
The words Waldo, structure, doubt and property were played to volunteers whose brains were wired up to a computer. The computer was able to recognise the words from the brain waves and then translate them into sounds and play them back.
Another professor from the project, Robert Knight, said that this could be great news for people whose speech has been damaged due to a stroke or paralysis. The NHS website Behind the Headlines says: ""This exciting and new research does raise the prospect of brain activity one day being translated into words using an implant. Such technology could help the vast numbers of people suffering from problems affecting speech. It is mind-boggling to think how else this technique could be used.
Should criminals be worried? Could police in the future forget about interviews and just plug suspects into a computer and listen to their minds? What about school - no need to respond to your teacher, the computer could detect your answers! Maybe we should all start practising having thoughts that we would be happy for others to eavesdrop on….
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