Atsuko Nagano-Saito

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OBJECTIVE Voxel-based morphometry was used to compare the amounts of gray matter in the brains of patients with Parkinson disease (PD) and normal control subjects (NCs) and to identify the specific regions responsible for cognitive dysfunction in PD. METHODS Patients were classified into nondemented (ND) and demented (D) groups according to the criteria(More)
We investigated the effect of transient dopamine depletion on functional connectivity during performance of the Wisconsin Card Sorting Task. Functional magnetic resonance imaging data were analyzed as a psychophysiological interaction, a statistical method used to identify functional connectivity during experimental manipulations. Nineteen healthy subjects(More)
OBJECTIVE Using 6-[(18)F]fluoro-L-dopa (FDOPA) and [(18)F]fluorodeoxyglucoce (FDG) positron emission tomography (PET), multiple regression analyses were performed to determine the specific brain regions that are related to cognitive and motor symptoms in nondemented patients with Parkinson's disease. METHODS Spatially normalized images of FDOPA influx(More)
Task-induced deactivation is frequently reported in the ventro-medial prefrontal cortex (vmPFC) and posterior cingulate cortex (PCC), regions considered to belong to the default mode network. To investigate the effect of dopamine on task-induced deactivation, we used positron emission tomography to measure cerebral blood flow during performance of the Tower(More)
To determine the characteristics of cerebral glucose metabolism in Parkinson's disease patients with visual hallucinations, group comparison studies using [18F]fluorodeoxyglucose positron emission tomography were performed. Nondemented Parkinson's disease patients in advanced stages were classified into two groups: (1) patients without visual(More)
We have previously observed decreased activation of corticostriatal loops involved in planning (cognitive loop) and execution (motor loop) of a set shift in patients with early Parkinson's disease (PD) compared with control subjects. Here, we aimed to assess whether cognitive impairment in PD could drive these differences. Nondemented patients underwent a(More)
We investigated the relative differences in dopaminergic function through the whole brain in patients with Parkinson's disease without dementia (PD) and with dementia (PDD) using 6-[18F]fluoro-L-dopa (18F-dopa) PET and a voxel-by-voxel analysis. The 10 PD and 10 PDD patients were equivalently disabled, having mean scores of 3.2 +/- 0.6 and 3.2 +/- 0.7,(More)
During simple sensorimotor decision making, neurons in the parietal cortex extract evidence from sensory information provided by visual areas until a decision is reached. Contextual information can bias parietal activity during the task and change the decision-making parameters. One type of contextual information is the availability of reward for correct(More)
For the past 15 years, measurements of cerebral blood flow as an indicator of neuronal activity have been used to gain a better understanding of the neural basis of motor and cognitive deficits in Parkinson’s disease. The initial studies, using positron emission tomography, yielded results in keeping with the hypothesis that symptoms result from excessive(More)
The role of fronto-striatal regions in processing different language rules such as semantic and (grapho) phonological ones is still under debate. We have recently developed a lexical analog of the Wisconsin card sorting task which measures set-shifting abilities where the visual rules color, number, shape were replaced by three language ones: semantic,(More)