Abstract

Brain stimulation techniques allow for the search of crucial areas for a given function. Not always convergent with neuroimaging, TMS studies have targeted parietal areas critical for quantity representation, spatio-numerical links, numerical and non-numerical quantity, finger gnosis and calculation. TMS data indicate the intraparietal sulcus and surrounding areas in the left and right hemisphere as crucial for quantity processing, although left hemisphere might be dominant. Bilateral parietal loci are essential for calculation and bilateral parietal areas are behind the spatio-numerical link, which extends to frontal and posterior parietal sites. DCE studies to date have focused on the dominant hemisphere, have used calculation tasks and have found both dissociation and overlap between operations. An integrative view of positive findings and a focus on convergence and possible improvement is proposed. Although regularities are found between these techniques, more research is needed before arriving at conclusions that will have basic and clinical importance.