The Magnitude Representation of Small and Large Symbolic Numbers in the Left and Right Hemisphere: An Event-related fMRI Study

摘要

Numbers are known to be processed along the left and rightnintraparietal sulcus. The present study investigated hemisphericndifferences between the magnitude representation of small andnlarge symbolic numbers. To this purpose, an fMRI adaptationnparadigm was used, where the continuous presentation of a habituationnnumber was interrupted by an occasional deviantnnumber. The results presented a distance-dependent increasenof activation: larger ratios of habituation and deviant numberncaused a larger recovery of activation. Similar activation patternsnwere observed for small and large symbolic numbers, which isnin line with the idea of a more coarse magnitude representationnfor large numbers. Interestingly, this pattern of activationnwas only observed in the left parietal cortex, supporting thenrecently proposed idea of Ansari [Ansari, D. Does the parietalncortex distinguish between “10”, “Ten,” and Ten Dots? Neuron,n53, 165–167, 2007] that the left parietal cortex is specializednin the processing of encultured symbolically presentednnumbers. ■