title: Effects of long-term practice and task complexity on brain activities when performing abacus-based mental calculations: a PET study.
abstract: OBJECTIVE
  The aim of this study was to examine the neural bases for the exceptional mental calculation ability possessed by Chinese abacus experts through PET imaging.
  
  
  METHODS
  We compared the different regional cerebral blood flow (rCBF) patterns using (15)O-water PET in 10 abacus experts and 12 non-experts while they were performing each of the following three tasks: covert reading, simple addition, and complex contiguous addition. All data collected were analyzed using SPM2 and MNI templates.
  
  
  RESULTS
  For non-experts during the tasks of simple addition, the observed activation of brain regions were associated with coordination of language (inferior frontal network) and visuospatial processing (left parietal/frontal network). Similar activation patterns but with a larger visuospatial processing involvement were observed during complex contiguous addition tasks, suggesting the recruitment of more visuospatial memory for solving the complex problems. For abacus experts, however, the brain activation patterns showed slight differences when they were performing simple and complex addition tasks, both of which involve visuospatial processing (bilateral parietal/frontal network). These findings supported the notion that the experts were completing all the calculation process on a virtual mental abacus and relying on this same computational strategy in both simple and complex tasks, which required almost no increasing brain workload for solving the latter.
  
  
  CONCLUSIONS
  In conclusion, after intensive training and practice, the neural pathways in an abacus expert have been connected more effectively for performing the number encoding and retrieval that are required in abacus tasks, resulting in exceptional mental computational ability.
authors.affiliation: Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: Tung-Hsin
authors.initials: TH
authors.lastname: Wu
authors.forename: Chia-Lin
authors.initials: CL
authors.lastname: Chen
authors.forename: Yung-Hui
authors.initials: YH
authors.lastname: Huang
authors.forename: Ren-Shyan
authors.initials: RS
authors.lastname: Liu
authors.forename: Jen-Chuen
authors.initials: JC
authors.lastname: Hsieh
authors.forename: Jason J S
authors.initials: JJ
authors.lastname: Lee
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000502:physiology*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D008297:Male; D008433:Mathematics; D009434:Neural Pathways / Q000502:physiology; D010104:Oxygen Radioisotopes; D049268:Positron-Emission Tomography / Q000379:methods*; D011361:Professional Competence; D011932:Reading; D013647:Task Performance and Analysis; D055815:Young Adult
chemical_list: D010104:Oxygen Radioisotopes