Kazuyoshi Sakamoto

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The present study investigated the effects of simulator sickness, as an important bias factor on evaluation of emotional changes under the controlled condition of driving a car for 60 min at a constant speed (60 km/h) in a graphic simulator. Simulator sickness was measured and analyzed every 5 min using both subjective evaluation and physiological signals.(More)
The contribution of motor unit activity to a physiological tremor (hereafter called as tremor) in a middle finger is studied by both a power spectrum and a correlation analysis in which the correlation coefficient and the coherence spectrum are obtained when five kinds of loads, 0, 50, 100, 150, and 200 g, are added to the middle finger for two minutes in a(More)
BACKGROUND This study investigates coordination of the upper-limb segments with various external loads by frequency-domain analysis of physiological tremor during the maintenance of limb posture. Physiological tremor is an involuntary oscillation in every segment of a healthy human. MATERIAL/METHODS A subject raised his right upper limb forward while(More)
A mathematical model for a physiological tremor of a finger, hereafter referred to as tremor, has been developed in order to evaluate the variation of amplitudes and frequencies at two peaks obtained in the power spectrum of the tremor under two conditions: (a) four loads of weight, 50, 100, 150, and 200 g, are added to the finger (state of load of weight),(More)
To investigate the influence of gravity on physiological tremor during a holding stretch of the finger, tremor during immersion of the finger in liquids was measured. Liquids with various densities and various coefficients of viscosity were used. Tremor was detected using an acceleration sensor, and power spectrum analysis was performed on the acceleration(More)
This study examined the effects of a different number of eccentric contractions (ECs) on histological characteristics, surface electromyogram (EMG) parameters (integral EMG, iEMG; muscle fiber conduction velocity, MFCV; and action potential waveform), and isometric peak torque using the rat EC model. Male Wistar rats (n = 40) were anesthetized, and ECs were(More)
The acceleration signal produced by physiological tremor from four different upper limb segments (the finger, hand, forearm and upper limb) was measured by an acceleration sensor during holding posture and was analyzed by power spectrum analysis. Two prominent peaks appeared in the power spectrum, suggesting that the tremor in the four different limb(More)
A model of feedback type in which physiological tremor are produced by both muscular skeletal system and reflex action is described. Analysis of this model shows that the interaction between the spinal and the supraspinal reflex pathways is important in responsible for low and high frequency oscillations of physiological tremor. Particularly the effect of(More)
To investigate the changes of cortico-cortical connectivity during odor stimulation of subjects classified by occupation, the mutual information content of EEGs was examined for general workers, perfume salespersons and professional perfume researchers. Analysis of the averaged-cross mutual information content (A-CMI) from the EEGs revealed that among the(More)
The effect of pseudo-fraction gravity on physiological tremor of the human finger (finger tremor) has been examined experimentally by immersing an index finger into water at different immersion levels. The pseudo-fraction gravity, gamma G, was established by water buoyancy at immersion level omega, G being gravitation acceleration and gamma between zero and(More)