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The uterus is a physiological system consisting of a large number of interacting smooth muscle cells. The uterine excitability changes remarkably with time, generally quiescent during pregnancy, the uterus exhibits forceful synchronized contractions at term leading to fetus expulsion. These changes characterize thus a dynamical system susceptible of being studied through formal mathematical tools...
Electric fields are used in a range of applications, including gene transfection, electrochemotherapy of tumors and cardiac defibrillation. Despite the widespread use of electric fields, most of the theoretical and computational studies on discrete cellular tissue have focused on a single cell. In this work, we propose a hybrid finite element method to simulate the effects of external electric fields...
Our aim is to assess and quantify the exact effects of the induction of long term potentiation (LTP) on tonic inhibition and facilitation in a neural circuit within the hippocampal formation of neonatal rats. The neural circuit of interest in this paper is the perforant pathway-dentate gyrus synapse which serves as the first leg of the hippocampal trisynaptic circuit. A quantitative measure of the...
Nano red elemental selenium (Nano-Se), was demonstrated to be useful in medical and scientific researches. Here, we investigated the effects of Nano-Se on sodium currents on rat dorsal root ganglion neurons (DRG), using the whole-cell patch clamp method. Nano-Se reversibly decrease the INa(TTX-S) in a concentration-dependent, time-dependent and open-channel block manners without affecting INa(TTX-R)...
We present a refined method and design for building parylene neurocages for in vitro studies of live neural networks. Parylene neurocages are biocompatible and very robust, making them ideally suited for studying the synaptic connections between individual neurons to gain insight into learning and memory. The neurocage fabrication process incorporates electrodes into the neurocages to allow for stimulation...
Electrocorticogram recordings for neuroprosthetics provide an intermediate level of abstraction between EEG and microwire single neuron recordings. For adaptive filtering methodologies used in neuroprosthetics, extraction of spatio-control parameters remains a difficulty. Since amplitude modulation in extracellular recordings plays a key role in both neuronal activation and rate coding, seeking spatial...
Accurate cardiac tissue-based modeling using the bidomain equations requires the incorporation of fine-scale structures observed at the 50-100 micron level. By including such features we can more easily observe how defibrillation shocks lead to total depolarization of the heart. Several modeling studies that have investigated the effect of fine scale structures on defibrillation success have been...
Cardiac tissue heterogeneities can result in spatially dependent restitution properties. We propose a method for quantifying the dispersed nature of these restitution curves (RCs) over a large number of imaged pixels/locations. Cardiac propagation in response to point stimulation was recorded in cardiomyocyte monolayers with voltage-sensitive dye over a large field of view using high resolution imaging...
Small (down to 1 mV/mm) electric fields will polarize neurons by only a small amount; for this reason small electric fields have previously been considered to have no physiologically relevant effects. However, here we propose a novel mechanism by which the non-linear properties of single neurons 'amplify' very small electric fields. Specifically, an amplified change in timing of action potential firing...
Dentate granule cells receive inputs from the entorhinal cortex as the "perforant path". There are two components of the perforant path: the lateral component (LPP) and the medial component (MPP). LPP and MPP convey different sensory modality information. It remains elusive as to how signals from different inputs interact and integrate at the granule cell level. We attempted to address this...
A bidomain reaction-diffusion model of the human heart was developed and potentials resulting from normal depolarization and repolarization were compared with results from a compatible monodomain model. Comparisons were made for an empty isolated heart and for a heart with fluid-filled ventricles. Both sinus rhythm and ectopic activation were simulated. The model took 2 days on 32 processors to simulate...
Electric fields are used in a range of applications, including gene transfection, electrochemotherapy of tumors and cardiac defibrillation. Despite the widespread use of electric fields, most of the theoretical and computational studies on discrete cellular tissue have focused on a single cell. In this work, we propose a hybrid finite element method to simulate the effects of external electric fields...
We introduce cycle-linear hybrid automata (CLHA) and show how they can be used to efficiently model dynamical systems that exhibit nonlinear, pseudo-periodic behavior. CLHA are based on the observation that such systems cycle through a fixed set of operating modes, although the dynamics and duration of each cycle may depend on certain computational aspects of past cycles. CLHA are constructed around...
Cardiac tissue heterogeneities can result in spatially dependent restitution properties. We propose a method for quantifying the dispersed nature of these restitution curves (RCs) over a large number of imaged pixels/locations. Cardiac propagation in response to point stimulation was recorded in cardiomyocyte monolayers with voltage-sensitive dye over a large field of view using high resolution imaging...
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