Masayuki Kamba

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Signals in functional magnetic resonance imaging (fMRI) are influenced by physiological fluctuations in addition to local brain activity. We have proposed a dynamic system model-based technique for separation of signal changes related to brain activation inputs from those related to physiological fluctuations. We applied this technique to a visual fMRI(More)
OBJECTIVES To determine the relation between severity of obstructive sleep apnoea (OSA) and degree of cerebral metabolic impairment. METHODS Fifty five patients with habitual snoring and excessive daytime sleepiness underwent standard overnight polysomnography and magnetic resonance spectroscopy separately. Proton MR spectra were measured with two(More)
A functional magnetic resonance imaging (fMRI) study during Japanese 'kana' readings was performed on Japanese dyslexic children. Five dyslexic children (aged 9-12 years) and five healthy children (aged 9-11 years) were investigated. The fMRI examination was performed by getting these children to read sentences constructed from Japanese phonograms, 'kana',(More)
Thirty-one patients, aged 22-71 years, with nocturnal apneic episodes and/or habitual snoring were studied with magnetic resonance spectroscopy (MRS) and diagnostic polysomnography separately to determine whether accumulation of lactate caused by cerebral hypoxia during sleep is associated with sleep-disordered breathing (SDB), aging and co-morbidities(More)
Lip protrusion requires bilateral symmetrical movements of the facial muscles, but the laterality of the activated sensorimotor cortex corresponding to the area of the face activated during lip protrusion remains under discussion. In this study, blood-oxygenation-level-dependent (BOLD) responses in the sensorimotor cortex during non-verbal lip protrusion(More)
PURPOSE To determine regional differences in the relationship between neuronal activation and blood oxygenation level-dependent (BOLD) signal changes. MATERIALS AND METHODS We performed BOLD and perfusion-based studies on healthy adult volunteers (40 for BOLD and 20 for perfusion-based studies) with visual stimulation of varied extent in the visual field(More)
This study investigates by functional MRI (fMRI) the characteristics of processing activities at the retrosplenial cortex (RSC) and compares them to activities at the parahippocampal place area (PPA). A special categorical selectivity of the RSC in the recognition of buildings was elucidated. RSC activation-which is related to the processing of information(More)
We studied, with functional MRI, how neuronal processing for visual objects progresses in the human brain by measuring suppressive responses to stimulus pairs. Two concentric rectangular frames of slightly different sizes were presented such that the smaller frame was shown first, followed by the larger dominant frame, with interstimulus intervals of 0, 50(More)
OBJECTIVE To determine whether direct measurement of mean transit time from pixels over in-plane vessels on high spatial resolution echo planar imaging is a reliable method for quantitative assessment of cerebral circulation. METHODS AND MATERIALS Dynamic susceptibility contrast studies were performed using high spatial resolution echo planar imaging(More)
OBJECTIVES To examine the usefulness of magnetic resonance angiography (MRA) in detection of persistent trigeminal arteries (PTA). MATERIAL AND METHODS 3D-time-of-flight (TOF)-MRA images obtained from 1100 patients (798 males and 302 females aged 6-75 years with a mean of 55 years) at our and related institutions were examined retrospectively for PTA. The(More)
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