Kiyoshi Kotani

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A physiologically motivated, dynamical model of cardiovascular autonomic regulation is shown to be capable of generating long-range correlated and multifractal heart rate. Virtual disease simulations are carried out systematically to account for the disease-induced relative dysfunction of the parasympathetic and the sympathetic branches of the autonomic(More)
The purpose of this study is to evaluate the multiple effects of respiration on cardiovascular variability in different postures, by analyzing respiratory sinus arrhythmia (RSA) and respiratory-related blood pressure (BP) variations for systolic BP (SBP), diastolic BP (DBP), and pulse pressure (PP) in the respiratory-phase domain. The measurements were(More)
Spontaneous neuronal activity plays an important role in the development of the brain. Developmental changes in the spontaneous activity pattern of neuronal networks in vitro have been extensively studied by using the microelectrode array (MEA) recording system. However, little is known about the transition of spontaneous intracellular calcium dynamics, and(More)
Recent experimental studies suggest that there is evidence for a synchronization between human heartbeat and respiration. We develop a physiologically plausible model for this cardiorespiratory synchronization, and numerically show that the model can exhibit stable synchronization against given perturbations. In our model, in addition to the well-known(More)
We evaluated the respiratory modulation of heart rate, i.e., respiratory sinus arrhythmia (RSA), with respect to respiratory phase derived from an analytic signal from the lung volume curve, during spontaneous breathing and paced breathing with different patterns. The magnitudes and waveforms of RSA in the phase domain were similar regardless of breathing(More)
Respiratory sinus arrhythmia (RSA) is known as an index of cardiac vagal activity and useful to evaluate the response of the cardiovascular system to external stimuli. As an external stimulation, swallowing is known to strongly affect the cardiovascular system. However, the influence of swallowing and its relation with the autonomic nervous system remain(More)
BACKGROUND Working memory (WM) is a key function for various cognitive processes. Near-infrared spectroscopy (NIRS) is a powerful technique for noninvasive functional imaging. However, a study has yet to be published on the application of NIRS for evaluating WM performance. The objective was to evaluate NIRS for measuring WM performance. METHODS Subjects(More)
Rat superior cervical ganglion (SCG) neurons and ventricular myocytes (VMs) were co-cultured separately in a minichamber placed on a microelectrode-array (MEA) substrate. The minichamber, fabricated photolithographically using polydimethylsiloxane (PDMS), had 2 compartments, 16 microcompartments and 8 microconduits. The SCG neurons were seeded into one of(More)
Connection strength estimation is widely used in detecting the topology of neuronal networks and assessing their synaptic plasticity. A recently proposed model-based method using the leaky integrate-and-fire model neuron estimates membrane potential from spike trains by calculating the maximum a posteriori (MAP) path. We further enhance the MAP path method(More)
Performance degradation will be caused by a variety of interfering factors for pattern recognition-based myoelectric control methods in the long term. This paper proposes an adaptive learning method with low computational cost to mitigate the effect in unsupervised adaptive learning scenarios. We presents a particle adaptive classifier (PAC), by(More)