Non-invasive brain stimulation in mathematics learning

Mathematical competencies are considered as one of the key cognitive abilities that are acquired through schooling. They constitute not only a central component of human intelligence that is highly relevant for educational and occupational attainment; recent evidence suggests that they also play an at least similarly vital role in everyday life as literacy. Within educational neuroscience, much knowledge has already been acquired on how numbers are represented and processed in the brain. Considerably less is known about the brain mechanisms underlying the acquisition of mathematical knowledge and skills taught in school. This holds particularly true for arithmetic knowledge and skills, which represent an essential building block in the development of higher-order mathematical competencies and which are impaired in individuals with mathematical learning disabilities. Against this background, there is currently rapidly growing interest in non-invasive brain stimulation by means of transcranial electrical stimulation (tES). This method allows to influence the activity of selected brain regions, which can be used to determine the causal brain mechanisms underlying learning and, practically more important, to potentially support learning in individuals with learning disabilities. However, the small current body of evidence on tES effects does not provide a clear picture of the actual benefits of this method. The present project aims at systematically evaluating the potential of tES in supporting the acquisition of school-relevant arithmetic competencies and at investigating the neural mechanisms that are causally involved in these processes. Using neuroscience methods (including tES, magnetic resonance imaging, MRI, and electroencephalography, EEG), the following research questions shall be answered: (a) Which type of non-invasive brain stimulation is effective in supporting arithmetic learning? (b) What is the practical relevance of these effects? (c) Which brain mechanisms underlie successful arithmetic learning? (d) Do the stimulation effects on learning depend on individual differences (e.g., in mathematical skills)? The project consists of three studies. In Study 1, we compare the effects of different tES protocols on arithmetic learning and on accompanying brain activity. In Study 2, we scrutinize the observed effects by administering different stimulation intensities and investigating the role of individual differences. In Study 3, we simulate the acquisition of arithmetic competencies to investigate the benefits of tES to support long-term arithmetic learning and to comprehensively assess the underlying neuronal mechanisms. The obtained findings will constitute the first systematic evaluation of the potential of non-invasive tES in supporting school-relevant mathematical learning and will contribute to a better understanding of the brain mechanisms of successful mathematics learning.

Mathematical competencies are considered as one of the key cognitive abilities that are acquired through schooling. They constitute not only a central component of human intelligence; recent evidence suggests that they also play an at least similarly vital role in everyday life as literacy. However, a considerably large number of people have major difficulties in acquiring mathematical competencies. In addition to individuals suffering from a mathematical learning disorder (developmental dyscalculia, about 3-6 % of the population), more than a fifth of the adult populations in OECD countries show very poor mathematical skills. Against this background, there is strong interest into new ways to foster mathematics learning. In the research field of educational neuroscience, non-invasive brain stimulation by means of transcranial electrical stimulation (tES) has been regarded as a promising future means to support learning. This method allows to influence the activity of selected brain regions, which can be used to determine the causal brain mechanisms underlying learning and, practically more important, to potentially foster learning. However, the small body of evidence on tES effects does not yet provide a clear picture of the actual benefits of this method. The aim of the present project was to evaluate the potential of tES to support school-relevant arithmetic learning. First, we reviewed the current evidence on the effectiveness of non-invasive brain stimulation in the treatment of neurocognitive disorders including attention-deficit/hyperactivity disorder, developmental dyslexia, and developmental dyscalculia. We revealed a strong imbalance of research on the three disorders with dyscalculia being addressed only in one study so far. In addition, we identified several substantial problems of the research field such as the low comparability of the studies and weaknesses in experimental designs, and put forward concrete recommendations for future research. Second, we conducted the first systematic evaluation of six promising stimulation protocols to foster arithmetic learning in a single session. This study with 140 healthy adults revealed that one novel type of tES, transcranial alternating current stimulation (tACS), is most effective to foster the acquisition of arithmetic fact knowledge. Third, in a follow-up study we further investigated the effects of this type of tES in a multi-day arithmetic training that more closely resembles learning in school. Finally, in another study we demonstrated for the first time the potential of tES to support memory consolidation processes (and, thus, learning success) when applied during wakeful rest immediately after learning. These and other findings in the project have substantially advanced the research field on non-invasive brain stimulation and suggest that some types of tES are indeed promising to support school-related learning.