Neural substrates in judgment process while playing go: a comparison of amateurs with professionals.

A professional go player shows incomparable ability in judgment during go game. Positron emission tomography (PET) was used to investigate the neural substrates of professional go player's judgment process. Eight professional go players and six amateur players were instructed to think over silently in the opening-stage game (fuseki, territorial planning) problems and the life-or-death (tsume, checkmate judgment) problems presented on the monitor in front of them for 60 s of H2 15O PET scans and to state the answer afterwards. We found that in the territorial planning problems the parietal activation was equally observed in both groups with the additional prefrontal activation in the amateur group, and in the checkmate-decision problems the precuneus and cerebellum were activated in professionals while the premotor and parietooccipital cortices (visuospatial processing region) were extensively activated in amateurs. The comparison of the two groups showed stronger activations in the precuneus and cerebellum in the professionals in contrast to the premotor activation in amateurs during checkmate judgment. In addition, the cerebellum was remarkably activated in the higher ranking professional players. These findings suggested the cerebellum and precuneus play important roles in processing of accurate judgment by visual imagery and nonmotor learning memory processes in professional go players.