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.

Activation in the premotor cortex during mental calculation in patients with Alzheimer's disease: relevance of reduction in posterior cingulate metabolism.

In vivo brain imaging of people with Alzheimer's disease (AD) has suggested the presence of functional disintegration in the posterior-anterior brain network from the posterior cingulate cortex (PCC) to the prefrontal cortex. To investigate the relationship between the baseline posteromedial metabolism and prefrontal neural activity during cognitomnemonic tasks in AD patients, we measured both glucose metabolism at baseline and cerebral blood flow (CBF) during the execution of mental calculation tasks (serial number subtraction) in 10 early-stage AD patients and six healthy subjects. The present study employed positron emission tomography with (18)F-fluorodeoxyglucose and H(2)(15)O. Group comparison using the region-of-interest (ROI) method and voxel-based statistical parametric mapping (SPM99) showed significant reduction in glucose metabolism in the PCC of the AD group. The PCC metabolism in the AD group was negatively correlated with scores on the Mini-Mental State Examination and with correct responses to the arithmetic task. During the arithmetic task, regional CBF increased significantly in the left parietal and bilateral prefrontal cortices in the normal group, whereas the bilateral premotor cortices were significantly activated in the AD group. Regression analysis showed a significant inverse correlation between the premotor activation and the baseline PCC metabolism in the AD group. These results suggest that the premotor cortex plays a compensatory role in executing mental calculations in AD patients with reduced posteromedial functions, which might reflect the dynamic aspect of the pathophysiology of early AD.

[A case of infected subdural hematoma following chronic subdural hematoma irrigation].

A 71-year-old female complicating Parkinson disease and diabetes mellitus was admitted to our medical center for urinary tract infection one month after burr hole irrigation and drainage of left chronic subdural hematoma. Klebsiella pneumonia was detected in the bacterial culture of her urine. As antibiotic therapy started, her condition and peripheral white blood cell counts were improved. But consciousness level got worsened and right hemiparesis appeared. A CT scan showed re-accumulation of left subdural fluid so an emergent irrigation was performed. The old hematoma with slightly yellowish, bloody purulent fluid was found and an intracapsular drain was inserted. Klebsiella pneumonia was detected from the bacterial culture of the hematoma. After 10 days, a CT scan showed subdural fluid collection again, so, total hematoma capsule removal was performed. After the operation, her neurological and serological condition improved and she was discharged without any neurological deficits. Klebsiella pneumonia existing urinary tracts rarely infected subdural hematoma cavity via hematogenous dissemination. We must keep in mind this complication may occur when we see compromised host like this case. Total removal of infected hematoma capsule is considered as radical treatment.