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The responsible pathological mechanisms of essential tremor are not yet clear. In order to understand the mechanisms of the central network its sources need to be found. The cortical sources of both the basic and first “harmonic” frequency of essential tremor are addressed in this paper. The power and coherence were estimated using the multitaper method for EEG and EMG data from 6 essential tremor...
We present a reduced order finite element (FE) algorithm suitable for real-time nonlinear simulation of soft tissues. A dynamic FE formulation with explicit time integration is employed. We demonstrate significant computation acceleration by performing the time integration in a low-dimensional generalised basis, generated from a set of a priori training simulations. The key mechanism for the acceleration...
A re-entrant resonant cavity applicator system for non-invasive brain tumor hyperthermia treatments was presented. We have already confirmed the effectiveness of the heating properties of this heating system with cylindrical agar phantoms and with computer simulations. This paper describes the specific absorption rate (SAR) analysis of this heating system for non-invasive brain tumor hyperthermia...
The World Health Organization estimates depression as a serious threat to the health of millions of people worldwide. The purpose of this paper is to introduce the ongoing research devoted to the investigation of a possibility to use low-field electromagnetic stimulation of the human brain in the treatment of depressive disorder. In the course of the work the 3D models of transcranial magnetic stimulation...
Sound translation into neural message at the first auditory synapse is of prime importance for providing organism with sound environment. Here, we compiled experimental features of the primary auditory neurons into a computational model, composed of two distinct compartments (i.e., afferent bouton and axon). Simulation of the model closely reproduces the whole biophysical properties of both excitatory...
Since the diversification of the electromagnetic (EM) environment is spreading, it is essential to estimate the EM energy absorption rate [specific absorption rate (SAR)] of a pregnant woman's body and her fetus under various exposure situations. For example, if pregnant women work in jobs where they might wear business portable radios around their abdomens, they should also be concerned about this...
Paired-pulse stimulation is a standard protocol that has been used for decades to characterize dynamic systems: the differences in responses to two sequential identical stimuli as a function of inter-stimulus interval provide quantitative information on the dynamics of the system. In neuroscience, the paired-pulse protocol is also widely used at multiple levels of analysis, from behavioral conditioning...
Several stochastic models, with various degrees of complexity, have been proposed to model the neuronal activity from different parts of the human brain. In this paper, we use an Ornstein-Uhlenbeck Process (OUP) to model the spike activity recorded from the thalamus of a patient suffering from Essential Tremor at the time of implantation of the electrodes for Deep Brain Stimulation. From the recorded...
A new adaptive motor controller was constructed, and tested on the control of a 2-wheeled balancing robot in simulation and real world. The controller consists of a feedback (PD) controller and a cerebellar neuronal network model. The structure of the cerebellar model was configured based upon known anatomical neuronal connection in the cerebellar cortex. Namely it consists of 120 granular (Gr) cells,...
Transcranial Magnetic Stimulation (TMS) in the rat is a powerful tool for investigating brain function. However, the state-of-the-art experiments are considerably limited because the stimulation usually affects undesired anatomical structures. A simulation of a conductive shield plate placed between the coil stimulator and the rat brain during TMS is presented. The Finite Element (FE) method is used...
We aimed this study at verifying the appropriateness of bivariate time-varying autoregressive models in detecting EEG-EMG relationships and identifying the characteristics of myoclonus-related EEG changes in patients with two forms of progressive myoclonus epilepsy (PME). Our results indicate that TVAR analysis was able to detect the presence of prominent peaks of EEG-EMG coherence between the EMG...
The functional connectivity of the brain is investigated through the study of multivariate autoregressive models (MVAR) applied to multichannel EEG recordings. After the identification of the model, different indices can be calculated that are able to quantify direct and indirect functional connections between cortical areas. These methodology is used for the investigation of possible connectivity...
We studied the dynamical pattern of transmission involved in the information processing during cognitive experiments engaging working memory. The ensemble averaging approach was used to fit a multichannel autoregressive model to the EEG signals recorded during the transitive reasoning task. The short-time directed transfer function was estimated for finding dynamical patterns of functional connectivity...
The goal of this study is to investigate the regional distribution of the electric field (E-field) strength induced by electroconvulsive therapy (ECT), and to contrast clinically relevant electrode configurations through finite element (FE) analysis. An FE human head model incorporating tissue heterogeneity and white matter anisotropy was generated based on structural magnetic resonance imaging (MRI)...
The safety of electroconvulsive therapy (ECT) in patients who have deep brain stimulation (DBS) implants represents a significant clinical issue. A major safety concern is the presence of burr holes and electrode anchoring devices in the skull, which may alter the induced electric field distribution in the brain. We simulated the electric field using finite-element method in a five-shell spherical...
For effective stimulation with tDCS, spatial focality of induced electrical field (EF) is one of the important factors to be considered. Recently, there have been some studies to improve the spatial focality via different types of electrodes and their new configurations: some improvements using ring electrodes were reported over the conventional pad electrodes. However, most of these studies assumed...
Striatum (STR) is the major input stage of the basal ganglia (BG). It combines information from cortex, subthalamic nucleus (STN) and external globus pallidus (GPe), and projects to the output stages of the BG, where selection between concurrent motor programs is performed. Parkinson's disease (PD) reduces the concentration of dopamine (DA, a neurotransmitter) in STR and changes in the level of DA...
Electroconvulsive therapy (ECT) is the most effective treatment for severe depressive disorder, and yet the mechanisms of its therapeutic effects remain largely unknown. A novel computational model is presented in this study to simulate and investigate direct cortical excitation caused by bitemporal electroconvulsive therapy (BT ECT), using a finite element model (FEM) of the human head. The skull...
Much of our knowledge about the electric field distribution in transcranial current stimulation (tCS) still relies on results obtained from layered spherical head models. In this work we created a high resolution finite element model of a human head by segmentation of MRI images, and paid particular attention to the representation of the cortical sheet. This model was then used to calculate the electric...
Deep Brain Stimulation (DBS) is an effective surgical therapy for the treatment of movement disorders in Parkinson's disease (PD) and other neurological pathologies. DBS is known to modulate the spiking activity of the neurons within the basal ganglia, but how such modulation impacts the primary sensorimotor cortex is still uncertain. In this study a monkey was stimulated with DBS at several frequencies...
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