title: Effective connectivity of the multiplication network: a functional MRI and multivariate Granger Causality Mapping study.
abstract: Developmental neuropsychology and functional neuroimaging evidence indicates that simple and complex mental calculation is subserved by a fronto-parietal network. However, the effective connectivity (connection direction and strength) among regions within the fronto-parietal network is still unexplored. Combining event-related fMRI and multivariate Granger Causality Mapping (GCM), we administered a multiplication verification task to healthy participants asking them to solve single and double-digit multiplications. The goals of our study were first, to identify the effective connectivity of the multiplication network, and second, to compare the effective connectivity patterns between a low and a high arithmetical competence (AC) group. The manipulation of multiplication difficulty revealed a fronto-parietal network encompassing bilateral intraparietal sulcus (IPS), left pre-supplementary motor area (PreSMA), left precentral gyrus (PreCG), and right dorsolateral prefrontal cortex (DLPFC). The network was driven by an intraparietal IPS-IPS circuit hosting a representation of numerical quantity intertwined with a fronto-parietal DLPFC-IPS circuit engaged in temporary storage and updating of arithmetic operations. Both circuits received additional inputs from the PreCG and PreSMA playing more of a supportive role in mental calculation. The high AC group compared to the low AC group displayed a greater activation in the right IPS and based its calculation more on a feedback driven intraparietal IPS-IPS circuit, whereas the low competence group more on a feedback driven fronto-parietal DLPFC-IPS circuit. This study provides first evidence that multivariate GCM is a sensitive approach to investigate effective connectivity of mental processes involved in mental calculation and to compare group level performances for different populations.
authors: Department of Molecular Neuroscience, George Mason University, Fairfax, VA 22030, USA. fkrueger@gmu.edu
authors: Frank
authors: F
authors: Krueger
authors: Steffen
authors: S
authors: Landgraf
authors: Elke
authors: E
authors: van der Meer
authors: Gopikrishna
authors: G
authors: Deshpande
authors: Xiaoping
authors: X
authors: Hu
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001921:Brain / Q000098:blood supply* / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008433:Mathematics; D009434:Neural Pathways / Q000098:blood supply / Q000502:physiology; D010100:Oxygen / Q000097:blood; D025341:Principal Component Analysis; D011930:Reaction Time; D013997:Time Factors; D055815:Young Adult
chemical_list: D010100:Oxygen