Three-part zvukovoy analyzer in the brain helps us to distinguish between different tones in different voices.


For speech sounds, our brain uses a complex system of analysis. (Photo: carballo / Depositphotos.)

The superior temporal gyrus in the human brain. (Photo: djr339 / Flickr.com.) ”

It is not only what we say but how we speak. In order to properly understand the words of others, we must, of course, know the meaning of words, but, in addition, we need to listen carefully to the tone with which they say: speech sounds vary in length and height, and depending on the intonation rises or falls, the meaning of the utterance can change.

There are languages in which intonation has a deep semantic meaning (e.g ., in the Mandarin language there are four tones, and the value of a spoken phrase on each tone will be different), but in “normal”, naturalnych languages, intonation plays an important role; for example, take the sentence “John plays football”, which at one and the same word order, but with different intonation, will be either affirmative or interrogative, or you have an ironic tinge, etc.

On the other hand, we should not forget that the voices of all people are different, someone voice low, someone high, someone used to stretch the words that someone says very quickly. That is, to discern and correctly interpret the intonation is very, very difficult task, and it can be assumed that the brain has a special device.

Previously, neuroscientists have managed to figure out what tone and height of speech sounds following nerve centers in the temporal and frontal lobes of the cortex, in particular, to the “music of words” especially listening superior temporal gyrus. The experiments researchers from the University of California in San Francisco helped to understand how these centers work.

Edward Chang (Edward Chang) and his colleagues worked with patients with epilepsy who were surgically to remove a dangerous area of the brain generating seizures. In such cases, the patient is first subjected to “miniperl”, inserting brain electrodes reading brain electrical activity, you can see exactly where the epileptic activity starts. Usually in such cases, in parallel with medical treatment and some basic research. And now volunteers with electrodes in the head listened to a few simple sentences, each pronounced with a different intonation, and neuroscientists followed, as in the different intonation respond to nerve centers responsible for the analysis of a foreign language.

Researchers the result is found in the superior temporal gyrus of a group of neurons that evaluated the average height of speech sounds. At the same time, it also found other neurons that remained indifferent to the altitude, but reacted on phonemes as they are – these cells were engaged in that distinguished words sounding; thanks to them we don’t confuse the word “Sasha” with the word “football”, because the name and the name of the game sound different. Finally, the third group of neurons was assessed by the change in tone – they work in different ways depending on which word in the phrase carried an emphasis that sounded whether a question or a statement, etc.

The authors also built a model that allows to predict the activity of neurons zvukorezhiser in respect of certain sound parameters. The model was tested on several hundreds of phrases, spoken by different people, and modeled the activity is quite consistent with the behavior of real neurons (the complete results of the experiments described in the article in Science).

Thus, in the brain within a large zvukorezhissura analyzer managed to find three of subdivision that individually help us understand who says (referring to the analysis of the average height of speech, that is, in fact, the evaluation of the voice of a particular person), what he says (distinguishing between phonemes), and how it says (assessment of tone). Obviously, these subdivisions help not only to listen but to speak, and in the near future the authors are going to figure out how Zvukovye neurons work when you configure your own speech.