Kenichi Shibuya

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There are few observations of the activity of the bilateral motor cortex during prolonged exhaustive motor tasks. Knowing how the motor cortex modulates muscle fatigue or how information about fatigue affects motor cortex activities in healthy humans may help explain why fatigue is so prevalent in patients with neurological disorders. The purpose of the(More)
To examine the cerebral activity of the motor cortex during maximum movement, we measured regional cerebral blood flow (rCBF) in twelve normal volunteers, using near infrared spectroscopy (NIRS). Repetitive tapping of the right index finger was performed at 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, and 4.5 Hz, and during maximum effort (ME). The relative increase(More)
Using near-infrared spectroscopy (NIRS) techniques, it is possible to examine bilateral motor cortex oxygenation during a static motor task. Cortical activation was assumed to be reflected by increased oxygenation. The purpose of the present study was to examine the time course of oxygenation in the bilateral motor cortex during a low-intensity handgrip(More)
It is possible to examine bilateral primary motor cortex (M1) activation during a sustained motor task using near-infrared spectroscopy (NIRS), in which it is assumed that increased oxygenation reflects cortical activation. The purpose of this study was to examine bilateral M1 activation in response to graded levels of force production during a unilateral(More)
It remains unclear whether activation kinetics in the motor cortex area is affected by training. The purpose of the present study was to examine the effect of training on the motor cortex activation. To accomplish this, the correlation between maximal voluntary contraction and motor cortex (M1) activity was examined. Differences in the motor cortex(More)
The effect of fatiguing exercise on the ipsi- and contralateral frontal cortex has not been fully clarified. The purpose of this study was to investigate by near-infrared spectroscopy (NIRS) the frontal cortex oxygenation response to a prolonged fatiguing repetitive handgrip exercise performed at maximal voluntary contraction. It was found a significant(More)
Previous studies have investigated the relationship between prefrontal cortex activation and perceived exertion during prolonged exercise. However, the effect of perceived exertion on prefrontal cortex activity is confounded by exercise intensity. Therefore, the changes in prefrontal cortex activity in response to perceived exertion remain unclear. The(More)
The brain function controlling muscle force production is not yet fully understood. The purpose of this study was to examine bilateral primary motor cortex (M1) oxygenation during static-handgrip exercises performed with the right hand (60% maximal voluntary contraction; 10 s exercise/75 s rest; five sets). Twelve healthy, right-handed male subjects(More)
Near-infrared spectroscopy (NIRS) can be used to examine bilateral motor cortex activation during a sustained motor task in brain areas where increased oxygenation reflects cortical activation. This study examines the time course of activation of the bilateral motor cortex during a moderate-intensity handgrip task. Ten healthy right-handed male subjects(More)
It is generally thought that fatigue is modulated during prolonged exhaustive motor tasks by the bilateral motor cortex. It remains unclear, however, how fatigue is modulated during motor tasks and how information about fatigue affects motor cortex activities in healthy humans. These results may help explain why fatigue is so prevalent in patients with(More)