Are numbers special? The comparison systems of the human brain investigated by fMRI

Roi Cohen Kadosh, Avishai Henik, Orly Rubinsten, Harald Mohr, Halit Dori, Vincent Van De Ven, Marco Zorzi, Talma Hendler, Rainer Goebel, David E.J. Linden

Research output: Contribution to journalArticlepeer-review


Many studies have suggested that the intraparietal sulcus (IPS), particularly in the dominant hemisphere, is crucially involved in numerical comparisons. However, this parietal structure has been found to be involved in other tasks that require spatial processing or visuospatial attention as well. fMRI was used to investigate three different magnitude comparisons in an event-related-block design: (a) Which digit is larger in numerical value (e.g., 2 or 5)? (b) Which digit is brighter (e.g., 3 or 3)? (c) Which digit is physically larger (e.g., 3 or) ? Results indicate a widespread cortical network including a bilateral activation of the intraparietal sulci for all different comparisons. However, by computing contrasts of brain activation between the respective comparison conditions and applying a cortical distance effect as an additional criterion, number-specific activation was revealed in left IPS and right temporal regions. These results indicate that there are both commonalities and differences in the spatial layout of the brain systems for numerical and physical comparisons and that especially the left IPS, while involved in magnitude comparison in general, plays a special role in number comparison.

Original languageEnglish
Pages (from-to)1238-1248
Number of pages11
Issue number9
StatePublished - 2005
Externally publishedYes

Bibliographical note

Funding Information:
This work was partly supported by grants to R.C.K. from the German Academic Exchange Service (DAAD, Research Grants for Doctoral Candidates and Young Academics and Scientists), the Kreitman Foundation and the Max Planck Society (Minerva Seed Grant) and by a grant to A.H. from the Israel Science Foundation, funded by the Israel Academy of Sciences and Humanities. The authors are grateful to Jan Lammertyn for his helpful comments and to David Prvulovic, Kathrin Cohen Kadosh and Christoph Bledowski for their help at various stages of the project.


  • Distance effect
  • Intraparietal sulcus
  • Magnitude

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Cognitive Neuroscience
  • Behavioral Neuroscience


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