Can thoughts change the brain?


Brain-computer interfaces affect the structure of the brain substance

The effect of a so-called brain-computer interface (BCI, brain-computer interface) is based on the fact that the mere presentation of an action triggers already measurable changes in the electrical brain activity. These signals can be read out and converted via machine learning systems into control signals which can, for example, operate a computer or even move a prosthesis. In a recently published study, scientists from the Max Planck Institute for Human Cognitive and Brain Sciences, the State University of Navarra and the TU Berlin show that after just one hour of training with a brain-computer interface (BCI), significant changes in the brain the volunteers appeared – training with the BCI also has direct repercussions on the neuronal structure and function of the brain.

In a brain-computer interface (BCI, brain-computer interface), the mere presentation of an action triggers already measurable changes in the electrical brain activity. These signals can be read out via an EEG (electroencephalogram) and converted into control signals via mechanical learning systems.

© Elias Domsch

The recently published interdisciplinary study examined the influence of two different types of BCIs on the brains of subjects who had no prior experience with this technique. Task of the first subgroup was to imagine that they move their arm or their feet, so perform a task that claims the motor system of the brain. The second group of participants, on the other hand, received a task that addressed the visual center of the brain: they should recognize and count letters on a screen. Experience has shown that test persons achieve good results from the beginning on the visual task, which can not be improved by further training, while addressing the motor system of the brain is significantly more complex and requires practice. Before and after the respective experiments with the Brain Computer Interface, the subjects' brains were examined with a special imaging procedure – MRI (Magnetic Resonance Imaging) – to document potential changes.

"It is well-known that, for example, intensive physical training also has effects on the plasticity of the brain," says Till Nierhaus from the Max Planck Institute for Human Cognitive and Brain Sciences. Plasticity is the ability of the brain to change depending on how it is used. A distinction is made between functional plasticity, in which only the intensity of the signals between the individual synapses changes, or the structural plasticity. The latter is used when it comes to the change or even new formation of nerve cells. "We wondered if these effects on the plasticity of the brain also occur when the task in a BCI attempt is purely mental, so only thought, but not physically performed," said Carmen Vidaurre, a scientist at the State University of Navarre.

An hour of training showed effect

As a result, the scientists actually found measurable changes in exactly the brain regions that were specific to the type of task to be performed. So changes in the visual areas of the brain in the participants with the visual task and changes in the motor area in those who have trained in the imagination movements. Particularly interesting: The changes occurred within a very short time (one hour) with the BCI and not only after months of physical training. "Still open is the question of whether these changes would also show up, if the subjects would not receive any visual or cognitive feedback via the BCI system, that their brain signals could be successfully read," says Till Nierhaus from the Max Planck Institute in Leipzig. Institute. Overall, however, the results indicate that these brain training effects could be used therapeutically to specifically target specific brain regions.

"Especially the spatial specificity of the BCI effects could, for example, specifically target the brain regions that have suffered damage in stroke patients," says Arno Villringer, Director Max Planck Institute for Human Cognitive Neuroscience. "Machine learning processes serve as decoders or translators of BCI activity into actionable control signals," adds Klaus-Robert Müller, Professor of Machine Learning at the Technical University of Berlin. "Only in this way can the individual BCI activity be converted into control signals without a long training period. This tailor-made read-out of the BCI will be critical to whether the technology can be used in rehabilitation systems in the future. "

. (tagsToTranslate) Brain Computer Interfaces (t) Training (t) Brain alteration


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