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Electrical stimulation on the posterior tibial nerve is commonly used in the measurement of somatosensory evoked potential (SEP). To improve the efficiency of stimulation, the potential field and current density distributions under the surface electrodes were simulated with a three layer theoretical model. The mirror method was used to analyze the potential field of point charge. Integration of the...
The aim of this study is to investigate how firing patterns of neuron in hippocampus change with coupling effect between soma and dendrite via simulation of single neuron firings by a two-compartment (soma-dendrite) model. The results will help to understand how firing patterns relative to synaptic plasticity in further study. The neuron model used in this study consisted two compartments: the soma...
Very slow yogic breathing techniques provide valuable insights into mechanisms of autonomous nervous system regulation that are usually not available for human subjects. This paper presents results of eight sessions of Nadi Shodhana Pranayama practiced at rate of one breath per minute. We characterized statistic and spectral measures of heart rate variability before, during, and after exercises. Significant...
Dynamic synchronization between different brain regions has long been considered as the underlying neural mechanism of sensory, motor and cognitive functions. Practical methods of accurately quantifying this kind of dynamics by using scalp EEG are plagued by volume conduction effects and background noise. We propose a new method of measuring transient phase locking between independent components underlying...
We address an important problem in neurophysiology concerning the characterization of coupled neural oscillators from experimental data. The approach employs the formal mathematical description of the dynamics of weakly coupled oscillators by the phase model, and the recently developed methods for identification of directionality of coupling and estimation of coupling delays. We study neuron oscillator...
Cells are equipped with a host of receptors that can convert chemical signals into electrical ones. Cell-based biosensors take cells as sensing elements for detecting the intracellular/extracellular microenvironment and some special characteristics of cells selves. This paper presents the design of the cell-based biosensor and optimization of the automatic fluidic system that makes it feasible to...
Little is known about the mechanism that improves the capabilities of athletes by high, intensity interval training (HIT). This study was conducted to determine the neurophysiological changes due to HIT. Changes in surface electromyography (SEMG) in well-trained endurance cyclists due to the training were identified. Seven subjects (maximal oxygen uptake [VO2max] 64.6 plusmn 4.8 ml.kg-1.min-1, mean...
High-level upper-limb amputations result in prostheses with many degrees-of-freedom to be controlled, with very few control signals. A novel method for the control of myoelectric upper limb prostheses has been developed. By transferring the residual nerves to spare muscles in or near the residual limb, additional myoelectric control signals are created that allow the simultaneous control of multiple...
It has been a goal of neuroprosthesis researchers to develop a system, which could provide artificial vision to a large population of individuals with blindness. It has been demonstrated by earlier researches that stimulating the visual cortex area electrically can evoke spatial visual percepts, i.e. phosphenes. The goal of visual cortex prosthesis is to stimulate the visual cortex area and generate...
Decoding of kinematic variables from neuronal spike trains is important for neuroprosthetic devices. The spike trains from single units must be extracted from extracellular neural signals and thus spike detection and sorting procedure is essential. Since the spike detection and sorting procedure may yield considerable errors, decoding algorithm should be robust against spike train errors. Here we...
This paper presents a system developed for cognitive impairment evaluation and training. We integrate three different test modules in the system for decreasing the complexity of the system manipulation and increasing the completeness of various cognitive function evaluations. Besides the standard modules, including CPT and WCST, a new module to evaluate and train the cognitive ability in the three...
This paper presents a fully integrated and low power CMOS amplifier for neural signal recording. It consists of a band-filtering preamp and a current-mode instrumentation amplifier. The design approach and the noise optimization are briefly discussed. A 0.6 mum CMOS technology is used for the design of the amplifier IC. The simulation shows that it has a pass band from 59 Hz to 12.8 kHz and a mid-band...
Delivering drugs directly to the brain tissue opens new approaches to disease treatment and improving neural interfaces. Several approaches using neural prostheses have been made to deliver drugs directly with bypassing the blood-brain barrier (BBB). In this paper, we propose a new polymer-based flexible microelectrode with drug delivery capability. The probe was fabricated and tested for electrical...
We present the design of an automatic electrode monitoring system for activated iridium oxide (AIROF) microelectrodes. It's a valuable piece of instrument in use in our laboratory to monitor the "health" of chronic implanted microelectrodes before neural stimulation or recording experiments. It is capable of automatically measuring electrode voltage and current of a large number of electrodes...
Based on Poisson variability, the strength of cross-correlation of two spike trains was quantified by a cross-correlation index (CCI). Discriminant analysis with CCI was used to quantify the contribution of cross-correlation in stimulus feature discrimination in an ensemble of retinal ganglion cells. Compared with simulated Poisson cell pair, it was found that cross-correlation carried useful information...
The main purpose of this study is to investigate the effects of chronic electrical stimulation of acupuncture points on rat diabetic neuropathy. Diabetes mellitus was induced by a single dose of intravenous streptozotocin. The efficacies of several different protocols of electrical stimulation were compared. The evaluation measures included nerve conduction velocity, tactile threshold and blood perfusion...
Acupuncture relies on the use of fine needles being inserted into specific points with varying amounts of manual or external stimulation. The gate control theory states that acupuncture closes the gate to pain and blocks pain perception in the brain via stimulation of large nerve fibers. The particular research develops a mechanical manipulation of acupuncture to simulate physician with the insertion...
An optical/potential CMOS image sensor was designed and fabricated for bioimaging applications. The image sensor is capable to simultaneously sense an optical image and an on-chip potential image. Target applications of the sensor are on-chip (optical + potential) neural imaging and on-chip DNA microarray sensing. The sensor has a QCIF (176 times 144) pixel array with alternatively aligned optical/potential...
We report that basic fibroblast growth factor (bFGF) induces the release of glutamate in ES-derived neurons during early stages of differentiation. Changes of Ca2+ concentration labeled by fluorescence intensity occurred in response to minimal concentrations of glutamate. The Ca2+ concentration was changed more rapidly by bFGF than by glutamate during the early stages of differentiation of ES-derived...
Reflex responses play an important role in gravity resistance, balance maintenance and the reaction to perturbation during human walking and standing upright. In this study, aiming at the realization of artificial reflex for paralyzed people, whose reflexive system was also impaired to a certain degree because of the weakened afferent neural pathway, the reflex responses of normal subjects were measured...
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