Dynamic modelling of electrical current distribution in the deep structure of the brain

2005 ◽  
Author(s):  
R. Bayford
Keyword(s):  
Current Distribution ◽  
Deep Structure ◽  
Dynamic Modelling ◽  
Electrical Current ◽  
The Brain

Electromyography-Based Functional Electrical Stimulation (FES) in Rehabilitation

2020 ◽  
pp. 833-851
Author(s):  
Poulami Ghosh ◽  
Ankita Mazumder ◽  
Anwesha Banerjee ◽  
D.N. Tibarewala
Keyword(s):  
Spinal Cord ◽  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Muscle Activity ◽  
Small Amplitude ◽  
Electrical Current ◽  
Metabolic Responses ◽  
Stroke Patients ◽  
Cord Injury ◽  
The Brain

Loss or impairment in the ability of muscle movement or sensation is called Paralysis which is caused by disruption of communication of nerve impulses along the pathway from the brain to the muscles. One of the principal reasons causing paralysis is Spinal Cord Injury (SCI) and Neurological rehabilitation by using neuro-prostheses, based on Functional Electrical Stimulation (FES) is extensively used for its treatment. Impaired muscles are activated by applying small amplitude electrical current. Electromyography (EMG), the recording of biosignals generated by muscle activity during the application of FES can be used as the control signal for FES based rehabilitative devices. This method is predominantly used for restoring upper extremity functioning (wrist, hand, elbow, etc.), standing, walking (speed, pattern) in stroke patients. FES, collaborated with conventional methods, has the potential to be utilized as a useful tool for rehabilitation and restoration of muscle strength, metabolic responses etc. in paralyzed patients.

scholarly journals Dynamic Modelling of Interactions between Microglia and Endogenous Neural Stem Cells in the Brain during a Stroke

Mathematics ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 132 ◽  
Author(s):  
Awatif Jahman Alqarni ◽  
Azmin Sham Rambely ◽  
Ishak Hashim
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Dynamic Modelling ◽  
Dynamic Effect ◽  
Brain Cells ◽  
Activated Microglia ◽  
Model Studies ◽  
The Impact ◽  
The Brain ◽  
Endogenous Neural Stem Cells

In this paper, we study the interactions between microglia and neural stem cells and the impact of these interactions on the brain cells during a stroke. Microglia cells, neural stem cells, the damage on brain cells from the stroke and the impacts these interactions have on living brain cells are considered in the design of mathematical models. The models consist of ordinary differential equations describing the effects of microglia on brain cells and the interactions between microglia and neural stem cells in the case of a stroke. Variables considered include: resident microglia, classically activated microglia, alternatively activated microglia, neural stem cells, tissue damage on cells in the brain, and the impacts these interactions have on living brain cells. The first model describes what happens in the brain at the stroke onset during the first three days without the generation of any neural stem cells. The second model studies the dynamic effect of microglia and neural stem cells on the brain cells following the generation of neural stem cells and potential recovery after this stage. We look at the stability and the instability of the models which are both studied analytically. The results show that the immune cells can help the brain by cleaning dead cells and stimulating the generation of neural stem cells; however, excessive activation may cause damage and affect the injured region. Microglia have beneficial and harmful functions after ischemic stroke. The microglia stimulate neural stem cells to generate new cells that substitute dead cells during the recovery stage but sometimes the endogenous neural stem cells are highly sensitive to inflammatory in the brain.

scholarly journals Modeling of a Plasma Antenna with Inhomogeneous Distribution of Electron Density

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Zong-sheng Chen ◽  
Li-fang Ma ◽  
Jia-chun Wang
Keyword(s):  
Transmission Line ◽  
Electron Density ◽  
Radiation Pattern ◽  
Current Distribution ◽  
Electrical Current ◽  
Inhomogeneous Distribution ◽  
Equivalent Theory ◽  
Plasma Antenna ◽  
Density Distributions ◽  
Radiation Direction

The distribution of the electron density along a plasma antenna can influence the antenna’s performance. But little has been done in this regard in former studies. In this paper, a model of a practical plasma antenna with an inhomogeneous distribution of electron density is founded according to the transmission-line equivalent theory of a metal monopole, from which the current distribution and the radiation pattern of a plasma antenna with appropriate parameters are calculated. The results show that the electrical current distribution, the maximum radiation direction, and the beamwidth of a plasma antenna vary with electron density distributions. To validate the model, the plasma antenna with the same parameters is also simulated based on electromagnetic software HFSS. It is found that the results from the two ways are almost consistent.

RECURRENCE QUANTIFICATION ANALYSIS OF BODY RESPONSE TO FUNCTIONAL ELECTRICAL STIMULATION ON HEMIPLEGIC SUBJECTS

2012 ◽  
Vol 12 (03) ◽  
pp. 1250038
Author(s):  
U. RAJENDRA ACHARYA ◽  
WENWEI YU ◽  
SUBHAGATA CHATTOPADHYAY ◽  
KUANYI ZHU ◽  
E. Y. K. NG ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Electrical Current ◽  
Recurrence Quantification Analysis ◽  
The Body ◽  
Functional Movement ◽  
Nervous Stimulation ◽  
Recurrence Quantification ◽  
Quantification Analysis ◽  
The Brain

Hemiplegia means paralysis of half of the body. It commonly occurs following "stroke", which is due to impedance of blood supply to the brain, hence also termed as "cerebrovascular accident" (CVA). As a consequence of this, the brain tissues suffer from ischemic damage resulting in several symptoms, such as mere weakness, numbness to complete loss of power (paralysis). In order to restore or improve the lost functional movement of the body of the stroke-affected and hemiplegic subjects, a method called functional electrical stimulation (FES) has often been employed as the measure of rehabilitation. FES makes use of low levels of electrical current to activate the nerves and then the muscles, affected. The response of the body to this electrically triggered nervous stimulation could be recorded through different bio-signals. In our work, we measured the accelerometers of hemiplegic patient in two states; with FES and without FES. The nonlinear and nonstationary walking-function-related accelerometers are analyzed using recurrence plots (RP), which helps to visualize the dynamic behavior of the signals. The RPs of electromyography (EMG) signals with stimulation showed distinct periodicity and rhythm when compared to that without stimulation. In addition, we extracted recurrence quantification analysis (RQA) parameters from RP to quantify the obtained information from the RP. Lower values were observed for most of the RQA parameters with FES than obtained without FES. This also confirmed the fact that FES is very useful in bringing more order, rhythm and better control in the physical activities of hemiplegic people.

DBS Safety

2016 ◽  
Author(s):  
Erwin B. Montgomery
Keyword(s):  
Neural Networks ◽  
Adverse Effects ◽  
Human Activities ◽  
Healthcare Professionals ◽  
Electrical Current ◽  
Time Limit ◽  
Ecological System ◽  
Medical Complications ◽  
Psychosocial Consequences ◽  
The Brain

DBS is not just about passing electrical current charges into the brain, but rather DBS is integrated into a complex ecological system that involves not only electricity, but medications, biologics, rehabilitation, and a range of human issues including ethics, psychology, sociology, indeed, the full gamut of human activities. Furthermore, these human activities of concern include not only the patient and the patient’s family members, caregivers, and friends, but also physicians and healthcare professionals. Space and time limit the excursion here into these issues. The focus necessarily falls on issues directly related to DBS: the range of safety concerns, injury secondary to electricity, medical complications, adverse effects related to the activation of neural networks, and the potential psychosocial consequences of DBS.

Movement Disorders

2012 ◽  
Author(s):  
Mark Hallett ◽  
Alfredo Berardelli
Keyword(s):  
Movement Disorders ◽  
Electrical Current ◽  
Intracortical Inhibition ◽  
Clinical Results ◽  
Clinical Role ◽  
Direct Electrical Current ◽  
Therapeutic Uses ◽  
Low Levels ◽  
The Brain

This article focuses on the potential therapeutic uses of transcranial magnetic stimulation (TMS) in movement disorders. The brain can be stimulated with low levels of direct electrical current, called direct current polarization (tDCS). High-frequency repetitive TMS might increase brain excitability and be used for therapy in Parkinson's disease. Single sessions with TMS, however, have not proven to be very effective. Treatment with tDCS has been performed in some open studies with some success, but these results need confirmation. Physiological findings in dystonia reveal a decrease in intracortical inhibition. There have been a few studies of patients with Tourette's syndrome with mixed results. To date, clinical results with TMS in movement disorders have been mixed, and more work will be needed to clarify the potential clinical role of TMS.

Current Distribution in the Brain From Surface Electrodes

1968 ◽  
Vol 47 (6) ◽  
pp. 717???723 ◽  
Author(s):  
STANLEY RUSH ◽  
DANIEL A. DRISCOLL
Keyword(s):  
Current Distribution ◽  
Surface Electrodes ◽  
The Brain

scholarly journals On the Inverse EEG Problem for a 1D Current Distribution

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
George Dassios ◽  
George Fragoyiannis ◽  
Konstantia Satrazemi
Keyword(s):  
Current Distribution ◽  
Three Dimensional ◽  
Spherical Model ◽  
One Dimensional ◽  
Special Cases ◽  
Nonlinear Algebraic System ◽  
Arbitrary Location ◽  
Spherical Conductor ◽  
The Brain ◽  
A Current

Albanese and Monk (2006) have shown that, it is impossible to recover the support of a three-dimensional current distribution within a conducting medium from the knowledge of the electric potential outside the conductor. On the other hand, it is possible to obtain the support of a current which lives in a subspace of dimension lower than three. In the present work, we actually demonstrate this possibility by assuming a one-dimensional current distribution supported on a small line segment having arbitrary location and orientation within a uniform spherical conductor. The immediate representation of this problem refers to the inverse problem of electroencephalography (EEG) with a linear current distribution and the spherical model of the brain-head system. It is shown that the support is identified through the solution of a nonlinear algebraic system which is investigated thoroughly. Numerical tests show that this system has exactly one real solution. Exact solutions are analytically obtained for a couple of special cases.

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