Your brain maps out numbers, including integers and fractions

Research conducted by a team of scientists led by Stanislas Dehaene and Daniela Valério at the INSERM-CEA Cognitive Neuroimaging Unit in France has uncovered how the brain organizes numerical information. The findings, published in PLOS Biology on October 22, 2026, reveal that the brain creates a semantic map that represents both integers and fractions in a shared, organized system.

The study involved 20 native French speakers who were presented with a series of integers and fractions and asked to determine whether each number was larger or smaller than the previous. Using functional MRI (fMRI) scans, researchers measured the participants' brain activity as they compared the numbers. The scans revealed a distinct pattern of activity in the intraparietal sulcus, a brain region associated with numerical processing.

The research indicates that the intraparietal sulcus contains a spatial map of numerical magnitude, ranging from smaller to larger numbers. Surprisingly, the study also found that integers and fractions were processed differently; however, when comparing different types of numbers, both were processed within the same, shared system. Participants made more errors and took longer to correctly order numbers when fractions were involved compared to integers.

The study concludes that our brain organizes quantities, including fractions and integers, into a highly structured internal map. This organization may facilitate more efficient processing of quantities and mathematical decision-making.