Research team discovers: brain does not process sensory information sufficiently

The reason why some people are worse at learning than others has been revealed by a research team from Berlin, Bochum, and Leipzig, operating within the framework of the Germany-wide network “Bernstein Focus State Dependencies of Learning”. They have discovered that the main problem is not that learning processes are inefficient per se, but that the brain insufficiently processes the information to be learned. The scientists trained the subjects’ sense of touch to be more sensitive. In subjects who responded well to the training, the EEG revealed characteristic changes in brain activity, more specifically in the alpha waves. These alpha waves show, among other things, how effectively the brain exploits the sensory information needed for learning. “An exciting question now is to what extent the alpha activity can be deliberately influenced with biofeedback”, says PD Dr. Hubert Dinse from the Neural Plasticity Lab of the Ruhr-Universität Bochum. “This could have enormous implications for therapy after brain injury or, quite generally, for the understanding of learning processes.” The research team from the Ruhr-Universität, the Humboldt Universität zu Berlin, Charité – Universitätsmedizin Berlin and the Max Planck Institute (MPI) for Human Cognitive and Brain Sciences reported their findings in the Journal of Neuroscience.

Learning without attention: passive training of the sense of touch

How well we learn depends on genetic aspects, the individual brain anatomy, and, not least, on attention. “In recent years we have established a procedure with which we trigger learning processes in people that do not require attention”, says Hubert Dinse. The researchers were, therefore, able to exclude attention as a factor. They repeatedly stimulated the participants’ sense of touch for 30 minutes by electrically stimulating the skin of the hand. Before and after this passive training, they tested the so-called “two-point discrimination threshold”, a measure of the sensitivity of touch. For this, they applied gentle pressure to the hand with two needles and determined the smallest distance between the needles at which the patient still perceived them as separate stimuli. On average, the passive training improved the discrimination threshold by twelve percent—but not in all of the 26 participants. Using EEG, the team studied why some people learned better than others.

Imaging the brain state using EEG: the alpha waves are decisive

The cooperation partners from Berlin and Leipzig, PD Dr. Petra Ritter, Dr. Frank Freyer, and Dr. Robert Becker recorded the subjects’ spontaneous EEG before and during passive training. They then identified the components of the brain activity related to improvement in the discrimination test. The alpha activity was decisive, i.e., the brain activity was in the frequency range 8 to 12 hertz. The higher the alpha activity before the passive training, the better the people learned. In addition, the more the alpha activity decreased during passive training, the more easily they learned. These effects occurred in the somatosensory cortex, that is, where the sense of touch is located in the brain.

Researchers seek new methods for therapy

“How the alpha rhythm manages to affect learning is something we investigate with computer models”, says PD Dr. Petra Ritter, Head of the Working Group “Brain Modes” at the MPI Leipzig and the Berlin Charité. “Only when we understand the complex information processing in the brain, can we intervene specifically in the processes to help disorders”, adds Petra Ritter. New therapies are the aim of the cooperation network, which Ritter coordinates, the international “Virtual Brain” project, which her team collaborates on, and the “Neural Plasticity Lab”, chaired by Hubert Dinse at the RUB.

Learning is dependent on access to sensory information

A high level of alpha activity counts as a marker of the readiness of the brain to exploit new incoming information. Conversely, a strong decrease of alpha activity during sensory stimulation counts as an indicator that the brain processes stimuli particularly efficiently. The results, therefore, suggest that perception-based learning is highly dependent on how accessible the sensory information is. The alpha activity, as a marker of constantly changing brain states, modulates this accessibility.

Brain waves reveal video game aptitude

Scientists report that they can predict who will improve most on an unfamiliar video game by looking at their brain waves. They describe their findings in a paper in the journal Psychophysiology.

The researchers used electroencephalography (EEG) to peek at electrical activity in the brains of 39 study subjects before they trained on Space Fortress, a video game developed for cognitive research. The subjects whose brain waves oscillated most powerfully in the alpha spectrum (about 10 times per second, or 10 hertz) when measured at the front of the head tended to learn at a faster rate than those whose brain waves oscillated with less power, the researchers found. None of the subjects were daily video game players.

The EEG signal was a robust predictor of improvement on the game, said University of Illinois postdoctoral researcher and Beckman Fellow Kyle Mathewson, who led the research with psychology professors and Beckman Institute faculty members Monica Fabiani and Gabriele Gratton.

“By measuring your brain waves the very first time you play the game, we can predict how fast you’ll learn over the next month,” Mathewson said. The EEG results predicted about half of the difference in learning speeds between study subjects, he said.

Alpha Waves Close Your Mind for Distraction, but Not Continuously, Research Suggests

Alpha waves were long ignored, but gained interest of brain researchers recently. Electrical activity of groups of brain cells results in brain waves with different amplitudes. The so-called alpha wave, a slow brain wave with a cycle of 100 milliseconds, seems to play a key role in suppressing irrelevant brain activity. The current hypothesis is that this alpha wave is associated with pulses of inhibition (every 100 ms) in the brain.

Mathilde Bonnefond and Ole Jensen (Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen) discovered that when distracting information can be anticipated in time there is an increase of the power of this alpha wave just before the distracter. Furthermore, the brain is able to precisely control the alpha wave so that the pulse of inhibition is maximal when the distracter appears. Indeed, between pulses of inhibition, there is still a window where the brain is excitable.

'It is like briefly opening a door to look what's happening outside. This enables us to detect an unexpected but important or dangerous event. But to avoid to be distracted by completely irrelevant information, it is better if the inhibition is active when a distracter is presented. It could be seen as a mechanism slamming the door of the brain on intruders'. The results are published by the scientific journal Current Biology at October 4.