The neurocognitive development of symbolic number representations.

Mathematical abilities are needed for everyday life (e.g., to interpret information boards in the supermarket), yet many children have difficulties in acquiring these elementary calculation skills. Research suggests that these difficulties are originate from impairments in processing numerical symbols or Arabic digits. The exact nature of these impairments remains unclear. Some authors suggest that the crucial problem is associating numerical symbols with an already existing (innate) magnitude representation. Another possibility is that impairments in processing numerical symbols are due to inefficient associations between symbolic numerical stimuli in a separate representational system. This project will disentangle both hypotheses by investigating the performance of children on a mixed (e.g., symbolic-non-symbolic) and a pure (e.g., two symbols) mapping task and by correlating the performance on these tasks with their scores on a standardized math test. We will also investigate how children with dyscalculia perform on both mapping tasks. Furthermore, we will investigate which brain areas are responsible for both types of mapping with Transcranial Magnetic Stimulation (TMS), a neuroimaging technique used to induce virtual lesions. Finally, we will set up an intervention study to examine the effect of training these mapping processes on behavioral and neural responses.