title: The functional architectures of addition and subtraction: Network discovery using fMRI and DCM.
abstract: The neuronal mechanisms underlying arithmetic calculations are not well understood but the differences between mental addition and subtraction could be particularly revealing. Using fMRI and dynamic causal modeling (DCM), this study aimed to identify the distinct neuronal architectures engaged by the cognitive processes of simple addition and subtraction. Our results revealed significantly greater activation during subtraction in regions along the dorsal pathway, including the left inferior frontal gyrus (IFG), middle portion of dorsolateral prefrontal cortex (mDLPFC), and supplementary motor area (SMA), compared with addition. Subsequent analysis of the underlying changes in connectivity - with DCM - revealed a common circuit processing basic (numeric) attributes and the retrieval of arithmetic facts. However, DCM showed that addition was more likely to engage (numeric) retrieval-based circuits in the left hemisphere, while subtraction tended to draw on (magnitude) processing in bilateral parietal cortex, especially the right intraparietal sulcus (IPS). Our findings endorse previous hypotheses about the differences in strategic implementation, dominant hemisphere, and the neuronal circuits underlying addition and subtraction. Moreover, for simple arithmetic, our connectivity results suggest that subtraction calls on more complex processing than addition: auxiliary phonological, visual, and motor processes, for representing numbers, were engaged by subtraction, relative to addition. Hum Brain Mapp 38:3210-3225, 2017. © 2017 Wiley Periodicals, Inc.
authors.affiliation: Beijing Advanced Innovation Center for Future Internet Technology, Beijing University of Technology, Beijing, China.|Department of Life Science and Informatics, Maebashi Institute of Technology, Maebashi, Japan.|Beijing International Collaboration Base on Brain Informatics and Wisdom Services, Beijing, China.|Beijing Key Laboratory of MRI and Brain Informatics, Beijing, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Beijing Advanced Innovation Center for Future Internet Technology, Beijing University of Technology, Beijing, China.|Department of Life Science and Informatics, Maebashi Institute of Technology, Maebashi, Japan.|International WIC Institute, Beijing University of Technology, Beijing, China.|Beijing International Collaboration Base on Brain Informatics and Wisdom Services, Beijing, China.|Beijing Key Laboratory of MRI and Brain Informatics, Beijing, China.
authors.forename: Ning
authors.identifier: 0000-0001-5387-8640
authors.initials: N
authors.lastname: Zhong
authors.affiliation: The Wellcome Trust Centre for Neuroimaging, University College London, London, UK.
authors.forename: Karl
authors.initials: K
authors.lastname: Friston
authors.affiliation: Department of Systems Life Engineering, Maebashi Institute of Technology, Maebashi, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Imamura
authors.affiliation: Beijing Advanced Innovation Center for Future Internet Technology, Beijing University of Technology, Beijing, China.|International WIC Institute, Beijing University of Technology, Beijing, China.|Beijing International Collaboration Base on Brain Informatics and Wisdom Services, Beijing, China.|Beijing Key Laboratory of MRI and Brain Informatics, Beijing, China.
authors.forename: Shengfu
authors.initials: S
authors.lastname: Lu
authors.affiliation: Beijing Advanced Innovation Center for Future Internet Technology, Beijing University of Technology, Beijing, China.|International WIC Institute, Beijing University of Technology, Beijing, China.|Beijing International Collaboration Base on Brain Informatics and Wisdom Services, Beijing, China.|Beijing Key Laboratory of MRI and Brain Informatics, Beijing, China.
authors.forename: Mi
authors.initials: M
authors.lastname: Li
authors.affiliation: Beijing Advanced Innovation Center for Future Internet Technology, Beijing University of Technology, Beijing, China.|International WIC Institute, Beijing University of Technology, Beijing, China.|Beijing International Collaboration Base on Brain Informatics and Wisdom Services, Beijing, China.|Beijing Key Laboratory of MRI and Brain Informatics, Beijing, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Beijing Advanced Innovation Center for Future Internet Technology, Beijing University of Technology, Beijing, China.|International WIC Institute, Beijing University of Technology, Beijing, China.|Beijing International Collaboration Base on Brain Informatics and Wisdom Services, Beijing, China.|Beijing Key Laboratory of MRI and Brain Informatics, Beijing, China.
authors.forename: Haiyuan
authors.initials: H
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of MRI and Brain Informatics, Beijing, China.|Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China.
authors.forename: Kuncheng
authors.initials: K
authors.lastname: Li
authors.affiliation: Ubiquitous Awareness and Intelligent Solutions Lab, Lanzhou University, Lanzhou, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Hu
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000502:physiology; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008433:Mathematics; D008959:Models, Neurological; D009434:Neural Pathways / Q000000981:diagnostic imaging* / Q000502:physiology; D010100:Oxygen / Q000097:blood; D011340:Problem Solving / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: arithmetic processing; dynamic causal modeling; fMRI; network discovery