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.
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 12%—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
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
"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.
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.