title: Format-dependent representations of symbolic and non-symbolic numbers in the human cortex as revealed by multi-voxel pattern analyses.
abstract: Neuroimaging studies in the last 20 years have tried to unravel the neural correlates of number processing across formats in humans and non-human primates. Results point to the intraparietal sulcus as the core area for an abstract representation of numerical quantity. On the other hand, there exist a variety of behavioral and neuroimaging data that are difficult to reconcile with the existence of such an abstract representation. In this study, we addressed this issue by applying multi-voxel pattern analysis (MVPA) to functional Magnetic Resonance Imaging (fMRI) data to unravel the neural representations of symbolic (digits) and non-symbolic (dots) numbers and their possible overlap on three different spatial scales (entire lobules, smaller regions of interest and a searchlight analysis with 2-voxel radius). Results showed that numbers in both formats are decodable in occipital, frontal, temporal and parietal regions. However, there were no overlapping representations between dots and digits on any of the spatial scales. These data suggest that the human brain does not contain an abstract representation of numerical magnitude.
authors.affiliation: Laboratory of Biological Psychology, University of Leuven (KU Leuven), Tiensestraat 102, B-3000 Leuven, Belgium; Parenting and Special Education Research Unit, University of Leuven (KU Leuven), Leopold Vanderkelenstraat 32, B-3000 Leuven, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Bulthé
authors.affiliation: Parenting and Special Education Research Unit, University of Leuven (KU Leuven), Leopold Vanderkelenstraat 32, B-3000 Leuven, Belgium. Electronic address: bert.desmedt@ppw.kuleuven.be.
authors.forename: B
authors.initials: B
authors.lastname: De Smedt
authors.affiliation: Laboratory of Biological Psychology, University of Leuven (KU Leuven), Tiensestraat 102, B-3000 Leuven, Belgium. Electronic address: hans.opdebeeck@ppw.kuleuven.be.
authors.forename: H P
authors.initials: HP
authors.lastname: Op de Beeck
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D055641:Mathematical Concepts; D010775:Photic Stimulation; D060388:Support Vector Machine; D055815:Young Adult
keywords: Multi-voxel pattern analysis; Numbers; Numerical cognition; Parietal cortex; fMRI