What makes new connections in the brain

Live healthy : New deed - new brain

Very resilient and flexible; excellently structured and organized; open to new ideas and always ready to learn; extremely adept at using existing networks and establishing new ones. - What sounds like the requirement profile in a job advertisement is actually: a description of the state of the human brain. This highly complex organ in the head, which makes up only around two percent of a person's weight, but still uses around 20 percent of the energy consumed, actually combines all these virtues that have been so much in demand on the job market for years: It is specialized but not stuck; it keeps track of things, but also takes care of the details; it is innovative and does not shy away from making mistakes in search of the best practice - in order to learn from them.
How it does all of this is not yet fully understood. Science is also still working on a final answer to the question of what exactly is going on in the head of a person who is learning something new - be it writing, driving a car or using a smartphone. "There is still no general concept here," says Arno Villringer, Director of the Neurology Department at the Max Planck Institute for Human Cognitive and Brain Sciences. Nevertheless, some of what goes on in the human head during learning is now known.

A realization which the scientists were able to make: the philosophical formula »Panta rhei« (ancient Greek for »everything flows«), which Heraklitus (520-460 BC) also put into the formulation that one could »not step into the same river twice«, The same also applies to the brain - only that the researchers express this in today's scientific language, English: "You never use the same brain twice". "The brain changes in everything it does," says Villringer. "If two brain cells are active in a row, they change themselves and also the connection between each other." The reason for this is that the brain adapts to everything it does. So it reacts very flexibly to the stimuli, signals and feedback it receives.
According to another finding of the scientists, this adaptive capacity is particularly great when something new, something unexpected happens. "The brain always has a certain idea of ​​what is around it," says Villringer. “Based on this, it tries to foresee what will happen next in order to be able to react appropriately.” This habit of the organ is also known as “predictive coding”. Since the things that we are just learning are naturally new, the brain's prediction does not occur in these cases - a so-called "prediction error" occurs. The brain then tries to eradicate this - by adapting to the new circumstances and impressions. "Imagine you want to learn to play the piano," says Villringer. “At first you are completely unfamiliar with the steps involved, you have no idea what happens when you press a key. At first glance, a tone therefore represents a prediction error. But over time and after a few repetitions, the brain not only knows that there are tones behind the keys - it also knows which ones: it has learned. "

This learning process runs in several phases. That is a third insight that science has today. The individual phases, in turn, take place in different of the many subunits of the brain, depending on what has to be learned and how far this process has already progressed. Regardless of whether it is about speaking, knitting or controlling a space shuttle, the basic course of the learning process in the brain is always the same: "At first everything happens very consciously, every movement has to be actively controlled," says Villringer. With an increasing number of repetitions, however, the level of concentration that is required slowly decreases: a process is then only carried out semi-consciously. If you have only become a master through further practice, a program then only needs to be started - what you have learned then runs more or less automatically.
In the example of the budding piano virtuoso, this means that at first he has to think carefully about which keys should be struck, how and in which order. The individual movements are deliberately controlled via the so-called primary motor cortex. "The more often a certain passage is repeated, the quicker and more error-free it is," says Villringer. In this phase, stronger and stronger connections develop between the primary and the so-called premotor cortex; the individual finger movements are less and less conscious. Primary and premotor cortex are two areas in the frontal lobe of the brain. Together they form the motor cortex that controls and controls movements - and changes accordingly when it learns something new. In motor learning such as playing the piano, these changes are usually completed after weeks or months of intensive practice, and the process of "playing the piano" is then permanently stored in the two areas like a program. It then appears as if the prefrontal cortex, which is also located in the frontal lobe, takes control. He ensures that actions are carried out appropriately. In simple terms, this means: the prefrontal cortex registers that the pianist is sitting in front of his instrument - and triggers the program »playing the piano«. This then runs completely automatically. Still, not all people can play the piano perfectly, even if they learn it right. Talent and interests also play a role in how well we master skills (see interview on page 14).
The ability of the brain to react flexibly to its environment, to adapt to changing circumstances and to learn is also known as neural plasticity: The connections between the individual brain cells and thus the structures as a whole are not rigid and fixed, but can depend on the requirements will be rebuilt. "This ability remains with us for a lifetime, even in old age," says neurologist Villringer.
The building work in the brain can be observed with the help of magnetic resonance or magnetic resonance imaging (MRI). "In the representation of the brain structure, certain areas become larger and denser over time as you learn," says Villringer. However, it is not - as previously assumed - that only individual areas of the brain are responsible for certain tasks: Complex functions in particular run rather over networks of different areas. According to Villringer, this can be observed by measuring the functional connectivity of the brain in a nuclear spin. The activity of the brain areas is measured - and how this is related in individual connection networks. "This connectivity changes as you learn," says Villringer: "New or more effective connections are created."

This is where the brain goes However, not necessarily planned and targeted before, but rather according to the experimental principle: According to Villringer, it was observed in experiments with mice that a multitude of new connections sprout in the mouse brain during learning - much more than was actually necessary and afterwards from the animals too were used. "So the brain seems to be testing various options," says Villringer. “The useless then perish again. Only what is efficient and needed remains. "
Even if the remodeling work and route tests in the brain last a lifetime, you still don't always learn everything equally well. Experts assume that there are certain phases of life that are particularly well suited for certain learning content: the critical periods. Why this is so has not yet been clarified. But it can be observed, for example, in attachment behavior, spatial vision and - for most people most clearly noticeable - in language learning. "Up to the age of ten, children learn languages ​​very quickly, almost playfully," says Villringer. After that it will be much harder. But it won't be impossible. So Hans can make up for Hänschen's learning failures - he just needs a lot longer and has to work harder.

Because of the neural plasticity and network structure, the brain is also able to compensate for damage caused by a stroke, for example - at least to a certain extent. "Here, too, the brain adapts and the networks reorganize," says Villringer. If one area fails, the neighboring brain regions and networks would try to take over its function. If an injury is too big, however, this no longer works or only works to a limited extent, so that, for example, many stroke patients make progress again in some areas, but others remain permanently damaged.
"At the moment, however, intensive research is being carried out into ways of supporting the brain of stroke patients in restructuring and relearning," says Villringer, who also holds an honorary professorship at the Clinic for Neurology at the Charité. For example, affected brain regions can be stimulated electromagnetically from the outside. Coupling learning to physical activity could also help, and finally drugs that activate the reward center. Because learning is particularly effective when progress is rewarded - through positive feedback from outside or through the release of the body's own messenger substance dopamine.
Regardless of whether the brain is damaged or in good health, the following applies: at some point it will be over. "The brain cannot grow infinitely," says Villringer. And its ability to maintain a number of well-developed effective networks side by side is also limited. "There always seems to be a kind of dynamic equilibrium here," says Villringer. This means that if one area is particularly large and well developed, another is smaller. And if certain networks are used and optimized particularly heavily, others become weaker. However, they tend not to dissolve completely, once what has been learned can be reactivated. Like the proverbial cycling - you don't forget that either.

The magazine for medicine and health in Berlin: "Tagesspiegel Gesund - Berlin's doctors for the brain and nerves".

Further topics of the edition: Fact check. Exciting information about the brain. What is intelligence About everyday skills, situational cunning and personality traits. Stay smart while playing. Wide awake into old age. Learn intelligence. 60 percent of human IQ is determined by genes - we have to learn the rest from childhood. Streamlines. Neurologists use electroencephalography to make brain waves visible - but what do the curves mean? The Stroke Mobile. Rapid help in the event of a stroke: a hospital on four wheels. Doctor's letter. How to recognize and treat strokes. Stroke rehab. After a cerebral infarction, the thinking organ has to reorganize. Long-term rehab.Relearn everyday life. Signal interference.Relieve tremors, cramps and stiff muscles - how brain pacemakers help against Parkinson's. Harbinger sleep disorder. A REM sleep behavior disorder indicates Parkinson's - and opens up new therapeutic approaches for medical professionals. On your own two feet. Multiple sclerosis doesn't have to end in a wheelchair. BSE goodbye? Did the danger begin? what happened to the mad cow epidemic? Thunderstorm in the brain. What helps with epilepsy. Furious pain. A cluster headache patient reports of perplexed doctors and incomprehensible fellow human beings. Hangover - without alcohol. Where the migraine attacks come from and what helps against the headache. Little bloodsuckers. Ticks are on the rise - and transmit dangerous pathogens. Lyme disease and TBE. How to recognize and treat tick diseases. Also: A comparison of clinics and rehabilitation centers."Tagesspiegel Gesund" - Now in our shop

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