Are numbers grounded in a general magnitude processing system? / Les nombres sont-ils ancrés dans un système de traitement général de la magnitude?

Sokolowski, H. M., Fias, W., Ononye, C. B., & Ansari, D. (2017). Are numbers grounded in a general magnitude processing system? A functional neuroimaging meta-analysis. Neuropsychologia. In Press.

DOI: http://dx.doi.org/10.1016/j.neuropsychologia.2017.01.019

HIGHLIGHTS / FAITS SAILLANTS

  • It is critical to synthesize inconsistent findings using quantitative meta-analyses. /
    Il est fort important de synthétiser les résultats incohérents ou contradictoires à l'aide de métaanalyses quantitatives.
     
  • Parietal and frontal lobes are activated by numerical and non-numerical magnitudes. /
    Les lobes pariétal et frontal sont activés dans le traitement de la magnitude numérique et non numérique.
     
  • Numerical and non-numerical magnitudes activate common and distinct brain regions. /
    Les traitements de la magnitude numérique et non numérique activent des régions cérébrales à la fois communes et distinctes.
     
  • Brain regions activated by numerical magnitudes depend on number formats. /
    Les régions activées par le traitement de la magnitude numérique dépend du format des nombres.


ABSTRACT

It is currently debated whether numbers are processed using a number-specific system or a general magnitude processing system, also used for non-numerical magnitudes such as physical size, duration, or luminance. Activation likelihood estimation (ALE) was used to conduct the first quantitative meta-analysis of 93 empirical neuroimaging papers examining neural activation during numerical and non-numerical magnitude processing. Foci were compiled to generate probabilistic maps of activation for non-numerical magnitudes (e.g. physical size), symbolic numerical magnitudes (e.g. Arabic digits), and nonsymbolic numerical magnitudes (e.g. dot arrays). Conjunction analyses revealed overlapping activation for symbolic, nonsymbolic and non-numerical magnitudes in frontal and parietal lobes. Contrast analyses revealed specific activation in the left superior parietal lobule for symbolic numerical magnitudes. In contrast, small regions in the bilateral precuneus were specifically activated for nonsymbolic numerical magnitudes. No regions in the parietal lobes were activated for non-numerical magnitudes that were not also activated for numerical magnitudes. Therefore, numbers are processed using both a generalized magnitude system and format specific number regions.

Keywords
Numerical magnitude; Non-numerical magnitude; Neural specialization; Functional magnetic resonance imaging; Symbolic; Nonsymbolic