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electrical physiology

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https://www.readbyqxmd.com/read/27918346/electrical-stimulation-for-seizure-induction-and-functional-mapping-in-stereoelectroencephalography
#1
Agnès Trébuchon, Patrick Chauvel
The challenge in epilepsy surgery is to remove the epileptogenic zone without compromising postoperative function. Electrical stimulation (ES) was developed to identify with greater anatomical and physiological precision cortical structures essential to language and motor function. Because the language network is widely distributed in the left (dominant) hemisphere, and often varies among patients, brain mapping should delineate eloquent areas at the individual level. Although ES for language is commonly performed during a presurgical investigation, the procedure remains nonstandardized among centers, and differences between grids and intracerebral depth electrodes (stereoelectroencephalography) should be taken into account when comparing results from different series...
December 2016: Journal of Clinical Neurophysiology: Official Publication of the American Electroencephalographic Society
https://www.readbyqxmd.com/read/27914377/evaluating-multipulse-integration-as-a-neural-health-correlate-in-human-cochlear-implant-users-relationship-to-spatial-selectivity
#2
Ning Zhou, Bryan E Pfingst
The decrease of psychophysical detection thresholds as a function of pulse rate for a fixed-duration electrical pulse train is referred to as multipulse integration (MPI). The MPI slopes correlate with anatomical and physiological indices of cochlear health in guinea pigs with cochlear implants. The aim of the current study was to assess whether the MPI slopes were related to the spatial spread of activation by electrical stimulation. The hypothesis was that MPI is dependent on the total number of excitable neurons at the stimulation site, with broader neural excitation producing a steeper threshold decrease as a function of stimulation rate...
September 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/27914225/cortical-stimulation-parameters-for-functional-mapping
#3
Jacquelyn A Corley, Pouya Nazari, Vincent J Rossi, Nora C Kim, Louis F Fogg, Thomas J Hoeppner, Travis R Stoub, Richard W Byrne
PURPOSE: There is significant variation in how patients respond to cortical electrical stimulation. It has been hypothesized that individual demographic and pathologic factors, such as age, sex, disease duration, and MRI findings, may explain this discrepancy. The purpose of our study is to identify specific patient characteristics and their effect on cortical stimulation, and discover the extent of variation in behavioral responses that exists among patients with epilepsy. METHOD: We retrospectively analyzed data from 92 patients with medically intractable epilepsy who had extra-operative cortical electrical stimulation...
November 23, 2016: Seizure: the Journal of the British Epilepsy Association
https://www.readbyqxmd.com/read/27911366/a-multimodal-imaging-and-stimulation-based-method-of-evaluating-connectivity-related-brain-excitability-in-patients-with-epilepsy
#4
Mouhsin M Shafi, Susan Whitfield-Gabrieli, Catherine J Chu, Alvaro Pascual-Leone, Bernard S Chang
Resting-state functional connectivity MRI (rs-fcMRI) is a technique that identifies connectivity between different brain regions based on correlations over time in the blood-oxygenation level dependent signal. rs-fcMRI has been applied extensively to identify abnormalities in brain connectivity in different neurologic and psychiatric diseases. However, the relationship among rs-fcMRI connectivity abnormalities, brain electrophysiology and disease state is unknown, in part because the causal significance of alterations in functional connectivity in disease pathophysiology has not been established...
November 13, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/27906709/looking-closer-at-acute-respiratory-distress-syndrome-the-role-of-advanced-imaging-techniques
#5
Giacomo Bellani, Jean-Jaques Rouby, Jean-Michel Constantin, Antonio Pesenti
PURPOSE OF REVIEW: Advanced imaging techniques have provided invaluable insights in understanding of acute respiratory distress syndrome (ARDS) and the effect of therapeutic strategies, thanks to the possibility of gaining regional information and moving from simple 'anatomical' information to in-vivo functional imaging. RECENT FINDINGS: Computed tomography (CT) led to the understanding of several ARDS mechanisms and interaction with mechanical ventilation. It is nowadays frequently part of routine diagnostic workup, often leading to treatment changes...
November 30, 2016: Current Opinion in Critical Care
https://www.readbyqxmd.com/read/27905618/mechanism-of-%C3%AE-synuclein-translocation-through-a-vdac-nanopore-revealed-by-energy-landscape-modeling-of-escape-time-distributions
#6
David P Hoogerheide, Philip A Gurnev, Tatiana K Rostovtseva, Sergey M Bezrukov
We probe the energy landscape governing the passage of α-synuclein, a natural "diblock copolymer"-like polypeptide, through a nanoscale pore. α-Synuclein is an intrinsically disordered neuronal protein associated with Parkinson's pathology. The motion of this electrically heterogeneous polymer in the β-barrel voltage-dependent anion channel (VDAC) of the mitochondrial outer membrane strongly depends on the properties of both the charged and uncharged regions of the α-synuclein polymer. We model this motion in two ways...
December 1, 2016: Nanoscale
https://www.readbyqxmd.com/read/27903834/saliva-diagnostics-current-views-and-directions
#7
Karolina Elżbieta Kaczor-Urbanowicz, Carmen Martin Carreras-Presas, Katri Aro, Michael Tu, Franklin Garcia-Godoy, David Tw Wong
In this review, we provide an update on the current and future applications of saliva for diagnostic purposes. There are many advantages of using saliva as a biofluid. Its collection is fast, easy, inexpensive, and non-invasive. In addition, saliva, as a "mirror of the body," can reflect the physiological and pathological state of the body. Therefore, it serves as a diagnostic and monitoring tool in many fields of science such as medicine, dentistry, and pharmacotherapy. Introduced in 2008, the term "Salivaomics" aimed to highlight the rapid development of knowledge about various "omics" constituents of saliva, including: proteome, transcriptome, micro-RNA, metabolome, and microbiome...
November 29, 2016: Experimental Biology and Medicine
https://www.readbyqxmd.com/read/27896810/multiple-pathways-for-elevating-extracellular-adenosine-in-the-rat-hippocampal-ca1-region-characterized-by-adenosine-sensor-cells
#8
Kunihiko Yamashiro, Yuki Fujii, Shohei Maekawa, Mitsuhiro Morita
Extracellular adenosine in the brain, which modulates various physiological and pathological processes, fluctuates in a complicated manner that reflects the circadian cycle, neuronal activity, metabolism, and disease states. The dynamics of extracellular adenosine in the brain are not fully understood, largely because of the lack of simple and reliable methods of measuring time-dependent changes in tissue adenosine distribution. This study describes the development of a biosensor, designated an adenosine sensor cell, expressing adenosine A1 receptor, and a genetically modified G protein...
November 5, 2016: Journal of Neurochemistry
https://www.readbyqxmd.com/read/27896005/cerebral-blood-flow-is-decoupled-from-blood-pressure-and-linked-to-eeg-bursting-after-resuscitation-from-cardiac-arrest
#9
Christian Crouzet, Robert H Wilson, Afsheen Bazrafkan, Maryam H Farahabadi, Donald Lee, Juan Alcocer, Bruce J Tromberg, Bernard Choi, Yama Akbari
In the present study, we have developed a multi-modal instrument that combines laser speckle imaging, arterial blood pressure, and electroencephalography (EEG) to quantitatively assess cerebral blood flow (CBF), mean arterial pressure (MAP), and brain electrophysiology before, during, and after asphyxial cardiac arrest (CA) and resuscitation. Using the acquired data, we quantified the time and magnitude of the CBF hyperemic peak and stabilized hypoperfusion after resuscitation. Furthermore, we assessed the correlation between CBF and MAP before and after stabilized hypoperfusion...
November 1, 2016: Biomedical Optics Express
https://www.readbyqxmd.com/read/27895926/non-invasive-brain-stimulation-as-a-tool-to-study-cerebellar-m1-interactions-in-humans
#10
REVIEW
Sara Tremblay, Duncan Austin, Ricci Hannah, John C Rothwell
The recent development of non-invasive brain stimulation techniques such as transcranial magnetic stimulation (TMS) has allowed the non-invasive assessment of cerebellar function in humans. Early studies showed that cerebellar activity, as reflected in the excitability of the dentate-thalamo-cortical pathway, can be assessed with paired stimulation of the cerebellum and the primary motor cortex (M1) (cerebellar inhibition of motor cortex, CBI). Following this, many attempts have been made, using techniques such as repetitive TMS and transcranial electrical stimulation (TES), to modulate the activity of the cerebellum and the dentate-thalamo-cortical output, and measure their impact on M1 activity...
2016: Cerebellum & Ataxias
https://www.readbyqxmd.com/read/27895596/reciprocal-modulation-of-ik1-ina-extends-excitability-in-cardiac-ventricular-cells
#11
Anthony Varghese
The inwardly rectifying potassium current (IK1) and the fast inward sodium current (INa) are reciprocally modulated in mammalian ventricular myocytes. An increase in the expression of channels responsible for one of these two currents results in a corresponding increase in expression of the other. These currents are critical in the propagation of action potentials (AP) during the normal functioning of the heart. This study identifies a physiological role for IK1-INa reciprocal modulation in ventricular fiber activation thresholds and conduction...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27893442/inconsistency-of-a-recently-proposed-method-for-assessing-magnetic-field-exposure-for-protection-against-peripheral-nerve-stimulation-in-occupational-situations
#12
Gernot Schmid, Rene Hirtl
A non-binding guide to practical implementation of European Directive 2013/35/EU concerning the limitation of occupational exposure against electromagnetic fields has been published recently. With regard to exposure assessment this guide proposes practically applicable assessment methods for non-uniform and non-sinusoidal environmental electric and magnetic fields, respectively. For non-sinusoidal magnetic fields in the low frequency range this guide proposes a time domain assessment (TDA) method, claimed to reduce the overestimation of exposure inherent to other assessment methods while being based on fundamental physiological principles regarding nerve stimulation...
November 28, 2016: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
https://www.readbyqxmd.com/read/27886604/a-low-cost-and-palm-size-analyzer-for-rapid-and-sensitive-protein-detection-by-ac-electrokinetics-capacitive-sensing
#13
Xiaozhu Liu, Cheng Cheng, Jayne Wu, Shigetoshi Eda, Yongcai Guo
Specific detection of protein biomarkers has a wide range of applications in areas such as medical science, diagnostics, and pharmacology. Quantitative detection of protein biomarkers in biological media, such as serum, is critically important in detecting disease or physiological malfunction, or tracking disease progression. Among various detection methods, electrical detection is particularly well suited for point-of-care (POC) specific protein detection, being of low cost, light weight and small form factor...
November 11, 2016: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/27883074/adipose-stem-cells-display-higher-regenerative-capacities-and-more-adaptable-electro-kinetic-properties-compared-to-bone-marrow-derived-mesenchymal-stromal-cells
#14
Ahmed El-Badawy, Marwa Amer, Reda Abdelbaset, Sameh N Sherif, Marwan Abo-Elela, Yehya H Ghallab, Hamdy Abdelhamid, Yehea Ismail, Nagwa El-Badri
Adipose stem cells (ASCs) have recently emerged as a more viable source for clinical applications, compared to bone-marrow mesenchymal stromal cells (BM-MSCs) because of their abundance and easy access. In this study we evaluated the regenerative potency of ASCs compared to BM-MSCs. Furthermore, we compared the dielectric and electro-kinetic properties of both types of cells using a novel Dielectrophoresis (DEP) microfluidic platform based on a printed circuit board (PCB) technology. Our data show that ASCs were more effective than BM-MSCs in promoting neovascularization in an animal model of hind-limb ischemia...
November 24, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27881388/hyperglycemia-induces-defective-ca2-homeostasis-in-cardiomyocytes
#15
Andrea Sorrentino, Giulia Borghetti, Yu Zhou, Antonio Cannata, Marianna Meo, Sergio Signore, Piero Anversa, Annarosa Leri, Polina Goichberg, Khaled Qanud, Jason T Jacobson, Thomas H Hintze, Marcello Rota
Diabetes and other metabolic conditions characterized by elevated blood glucose constitute important risk factors for cardiovascular disease. Hyperglycemia targets myocardial cells rendering ineffective mechanical properties of the heart, but cellular alterations dictating the progressive deterioration of cardiac function with metabolic disorders remain to be clarified. In the current study, we examined the effects of hyperglycemia on cardiac function and myocyte physiology by employing mice with high blood glucose induced by administration of streptozotocin, a compound toxic to insulin-producing β-cells...
November 23, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27879672/electric-signals-regulate-the-directional-migration-of-oligodendrocyte-progenitor-cells-opcs-via-%C3%AE-1-integrin
#16
Bangfu Zhu, Matthew Nicholls, Yu Gu, Gaofeng Zhang, Chao Zhao, Robin J M Franklin, Bing Song
The guided migration of neural cells is essential for repair in the central nervous system (CNS). Oligodendrocyte progenitor cells (OPCs) will normally migrate towards an injury site to re-sheath demyelinated axons; however the mechanisms underlying this process are not well understood. Endogenous electric fields (EFs) are known to influence cell migration in vivo, and have been utilised in this study to direct the migration of OPCs isolated from neonatal Sprague-Dawley rats. The OPCs were exposed to physiological levels of electrical stimulation, and displayed a marked electrotactic response that was dependent on β1 integrin, one of the key subunits of integrin receptors...
November 22, 2016: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/27875227/a-stretchable-microneedle-electrode-array-for-stimulating-and-measuring-intramuscular-electromyographic-activity
#17
Gareth S Guvanasen, Liang Guo, Ricardo J Aguilar, Ashton L Cheek, Chancellor S Shafor, Swaminathan Rajaraman, T Richard Nichols, Stephen P DeWeerth
We have developed a stretchable microneedle electrode array (sMEA) to stimulate and measure the electrical activity of muscle across multiple sites. The technology provides the signal fidelity and spatial resolution of intramuscular electrodes across a large area of tissue. Our sMEA is composed of a polydimethylsiloxane (PDMS) substrate, conductive-PDMS traces, and stainless-steel penetrating electrodes. The traces and microneedles maintain a resistance of less than 10 kΩ when stretched up to a ~63% tensile strain, which allows for the full range of physiological motion of feline muscle...
November 16, 2016: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/27873155/physiology-based-regularization-of-the-electrocardiographic-inverse-problem
#18
Matthijs J M Cluitmans, Michael Clerx, Nele Vandersickel, Ralf L M Peeters, Paul G A Volders, Ronald L Westra
The inverse problem of electrocardiography aims at noninvasively reconstructing electrical activity of the heart from recorded body-surface electrocardiograms. A crucial step is regularization, which deals with ill-posedness of the problem by imposing constraints on the possible solutions. We developed a regularization method that includes electrophysiological input. Body-surface potentials are recorded and a computed tomography scan is performed to obtain the torso-heart geometry. Propagating waveforms originating from several positions at the heart are simulated and used to generate a set of basis vectors representing spatial distributions of potentials on the heart surface...
November 21, 2016: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/27869707/ex-vivo-characterization-of-bioimpedance-spectroscopy-of-normal-ischemic-and-hemorrhagic-rabbit-brain-tissue-at-frequencies-from-10-hz-to-1-mhz
#19
Lin Yang, Ge Zhang, Jiali Song, Meng Dai, Canhua Xu, Xiuzhen Dong, Feng Fu
Stroke is a severe cerebrovascular disease and is the second greatest cause of death worldwide. Because diagnostic tools (CT and MRI) to detect acute stroke cannot be used until the patient reaches the hospital setting, a portable diagnostic tool is urgently needed. Because biological tissues have different impedance spectra under normal physiological conditions and different pathological states, multi-frequency electrical impedance tomography (MFEIT) can potentially detect stroke. Accurate impedance spectra of normal brain tissue (gray and white matter) and stroke lesions (ischemic and hemorrhagic tissue) are important elements when studying stroke detection with MFEIT...
November 18, 2016: Sensors
https://www.readbyqxmd.com/read/27867359/physiology-and-evolution-of-voltage-gated-calcium-channels-in-early-diverging-animal-phyla-cnidaria-placozoa-porifera-and-ctenophora
#20
Adriano Senatore, Hamad Raiss, Phuong Le
Voltage-gated calcium (Cav) channels serve dual roles in the cell, where they can both depolarize the membrane potential for electrical excitability, and activate transient cytoplasmic Ca(2+) signals. In animals, Cav channels play crucial roles including driving muscle contraction (excitation-contraction coupling), gene expression (excitation-transcription coupling), pre-synaptic and neuroendocrine exocytosis (excitation-secretion coupling), regulation of flagellar/ciliary beating, and regulation of cellular excitability, either directly or through modulation of other Ca(2+)-sensitive ion channels...
2016: Frontiers in Physiology
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