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Selective characteristic for functional electrical stimulation is very important for restoring lost motor or sensory functions. The stimulation should broadly generate action potentials with a stimulating electrode and simultaneously blocks unnecessary stimulation with given grounded ones. 1-, 2-, 3-, and 5-needle electrode arrays were designed and simulated with finite element software, respectively...
A general view of the recent bioelectromagnetic research and of its future perspectives is presented in this paper. Indeed open issues on the effects of radiofrequency and microwave low-level chronic exposure need further scientific clarifications. In this context, recent epidemiological studies are discussed as well as human, animal and cellular investigations. Prospective cohort studies of children...
Long term Behavioral and neurophysiological studies of freely moving animals require a wireless portable low power neurostimulator which can provide precisely controllable input(s) to the nervous system. In this paper, we have reported design of a long range, wireless neuro-stimulat or for electrical stimulation of central nervous system, optimized to consume ultra low power and therefore suitable...
Long term neurophysiological studies of un-anesthetized and freely moving animals require an implantable miniaturized telemetry system that can acquire and transmit neural firing patterns and other physiological parameters directly from inside the body. In this paper the design and in vitro results of a long range implantable bio-telemetry system is presented. This system has three main features:...
An inductively powered 32-channel wireless integrated neural recording system, capable of endless recording from small freely behaving animals, is reported. A power scheduling mechanism maintains the power consumption of the LNAs constant regardless of the number of channels. Closed-loop power transmission maintains the received power constant despite animal movements.
It has been long recognized that there are 2 methods for inducing VF (ventricular fibrillation) with electrical currents.. These are: (1) delivering a high-charge shock into the cardiac T-wave, and (2) delivering lower level currents for 1-5 seconds. Present electrical safety standards are based on this understanding. We present new data showing a 3rd mechanism of inducing VF which involves the steps...
Since the introduction of the Conducted Electrical Weapons (CEW) several studies have been conducted and multiple reports have been published on safety of these devices from a medical point of view. Use of these devices in different situations and reported deaths attracts media attention and causes general anxiety around these devices. These devices have several limitations- such as rate of fire or...
Brain's functional response can be studied by observing the spatiotemporal dynamics of functional and structural changes in cerebral vasculature. However, very few studies explore detailed changes at the level of individual microvessels while revealing the simultaneous wide field view of microcirculation responses to functional stimulation. Here we use a high spatiotemporal resolution laser speckle...
In this study, new aspects of our research regarding a novel hybrid system able to provide focused microwave radiometric temperature and/or conductivity measurements and hyperthermia treatment via microwave irradiation are presented. On one hand, it is examined whether the system is capable of sensing real-time progressive local variations of temperature and/or conductivity in customized phantom setups;...
Cross-sectional imaging of an electrical conductivity distribution inside the human body has been an active research topic in the field of impedance imaging. This paper describes the recent progress in magnetic resonance electrical impedance tomography (MREIT) where conductivity imaging with a spatial resolution of a few mm is pursued. After the early studies on its theory and image reconstruction...
In this invited session, we would like to address the impact of bionic neuromodulation on cardiovascular diseases. It has been well established that cardiovascular dysregulation plays major roles in the pathogenesis of cardiovascular diseases. This is the reason why most drugs currently used in cardiology have significant pharmacological effects on the cardiovascular regulatory system. Since the ultimate...
Introduction: Conducted electrical weapons (CEW) have generated controversy in recent years regarding their effect on heart rhythm and on their suspected interaction with implanted devices such as the pacemakers and ICDs (implantable cardioverter defibrillators). We review the current evidence available on device interactions and pre-sent a new case series of 6 patients. Literature: We used the available...
Devices employed in electrical policing rely on fundamental responses of nerve and muscle to supraphysiologic current to quell disruptive behavior. Whilst widely deployed the use of neuromuscular incapacitation (NMI) remains controversial, in part, due to gaps in understanding of the underlying mechanisms related to injury. NMI device manufacturers are thus constrained by empirical evidence for safety...
Radiotelemetred male Wistar outbrad rats and borderline hypertensive rats (BHR) were exposed to acute and chronic environmental stress. Approximate entropy (ApEn) approach is applied in order to investigate the pulse interval (PI) response to two different types of environmental stress: shaker and restrain stress. The performance of ApEn method was evaluated from the parameter selection point of view...
The delivery of high frequency alternating currents (HFAC) to peripheral nerves has been shown to produce a rapid and reversible nerve conduction block at the site of the electrode, and holds therapeutic promise for diseases associated with undesired or pathological neural activity. It has been known since 1939 that the configuration of an electrode used for nerve block can impact the quality of the...
To test the reliability of amplitude-integrated electroencephalogram (aEEG) in cerebral hypoxic ischemia (HI), 12 neonatal piglets subjected to different levels of HI are divided into three groups based on the histological outcomes obtained 4 days after experiment. Results show that concomitant with the increased severity of brain injury, the upper and lower margins of aEEG decrease significantly...
Intramyocardial reentry is implicated as a primary cause of the most deadly cardiac arrhythmias known as polymorphic ventricular tachycardia and ventricular fibrillation. However, the mechanisms involved in the triggering of such reentry and controlling its subsequent dynamics remain poorly understood. One of the major obstacles has been a lack of adequate tools that would enable 3D imaging of electrical...
Current density and electrical conductivity imaging research at the University of Toronto is reviewed. Methods for imaging live animals at low frequency are described and contrasted with EIT and other MRI based techniques. New work on imaging at radio frequencies is presented and future work directions are discussed. It is concluded that low frequency methods are mature and ready for application in...
Epilepsy is a devastating disease of the central nervous system, affecting ~1% of the world's population. Drug therapy is effective in many patients, but 25% of the patients do not respond to anticonvulsants. Surgical resection can be an effective treatment but is associated with serious complications that can remove it as an option. Electrical stimulation has been successful to control abnormal activity...
Experimentally observed differences in the action potential (AP) properties between the left (LA) and right (RA) atria are believed to be important in maintaining reentrant sources during atrial fibrillation. We incorporate AP models for single LA and RA cells, as well as major intra- and interatrial conduction pathways, into a 2D atrial tissue model and study the role of tissue heterogeneity in global...
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