title: Developmental specialization of the left parietal cortex for the semantic representation of Arabic numerals: an fMR-adaptation study.
abstract: The way the human brain constructs representations of numerical symbols is poorly understood. While increasing evidence from neuroimaging studies has indicated that the intraparietal sulcus (IPS) becomes increasingly specialized for symbolic numerical magnitude representation over developmental time, the extent to which these changes are associated with age-related differences in symbolic numerical magnitude representation or with developmental changes in non-numerical processes, such as response selection, remains to be uncovered. To address these outstanding questions we investigated developmental changes in the cortical representation of symbolic numerical magnitude in 6- to 14-year-old children using a passive functional magnetic resonance imaging adaptation design, thereby mitigating the influence of response selection. A single-digit Arabic numeral was repeatedly presented on a computer screen and interspersed with the presentation of novel digits deviating as a function of numerical ratio (smaller/larger number). Results demonstrated a correlation between age and numerical ratio in the left IPS, suggesting an age-related increase in the extent to which numerical symbols are represented in the left IPS. Brain activation of the right IPS was modulated by numerical ratio but did not correlate with age, indicating hemispheric differences in IPS engagement during the development of symbolic numerical representation.
authors.affiliation: Numerical Cognition Laboratory, Department of Psychology, The University of Western Ontario, London, ON, Canada; Section of Educational Neuroscience, Department of Psychology, University of Graz, Graz, Austria.
authors.forename: Stephan E
authors.initials: SE
authors.lastname: Vogel
authors.affiliation: Numerical Cognition Laboratory, Department of Psychology, The University of Western Ontario, London, ON, Canada.
authors.forename: Celia
authors.initials: C
authors.lastname: Goffin
authors.affiliation: Numerical Cognition Laboratory, Department of Psychology, The University of Western Ontario, London, ON, Canada. Electronic address: daniel.ansari@uwo.ca.
authors.forename: Daniel
authors.initials: D
authors.lastname: Ansari
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D008433:Mathematics; D010296:Parietal Lobe / Q000502:physiology*; D012660:Semantics
keywords: Developmental changes; Intraparietal sulcus (IPS); Number development; Number representation; Symbolic numerical magnitude; fMRI adaptation