Dissertations / Theses on the topic 'Electrophysiology'
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Lionetti, Fred. "GPU accelerated cardiac electrophysiology." Diss., [La Jolla] : University of California, San Diego, 2010. http://wwwlib.umi.com/cr/ucsd/fullcit?p1474756.
Full textTitle from first page of PDF file (viewed April 14, 2010). Available via ProQuest Digital Dissertations. Includes bibliographical references (p. 85-89).
Du, Peng 1985. "Mathematical modelling of gastric electrophysiology." Thesis, University of Auckland, 2011. http://hdl.handle.net/2292/10234.
Full textJeu, Marcel Theodorus Gerardus de. "Electrophysiology of the suprachiasmatic nucleus." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2001. http://dare.uva.nl/document/59002.
Full textKhosrovani, Sara. "Electrophysiology of the olivocerebellar loop." [S.l.] : Rotterdam : [The Author] ; Erasmus University [Host], 2008. http://hdl.handle.net/1765/12220.
Full textMalchano, Zachary John. "Image guidance in cardiac electrophysiology." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35515.
Full textMIT Institute Archives copy: Pages 101-130 bound in reverse order.
Includes bibliographical references (p. 123-130).
Cardiac arrhythmias are characterized by a disruption or abnormal conduction of electrical signals within the heart. Treatment of arrhythmias has dramatically evolved over the past half-century, and today, minimally-invasive catheter-based therapy is the preferred method of eliminating arrhythmias. Using an electroanatomical (EA) mapping system, which precisely tracks the position of catheters inside the patient's body, it is possible to construct three-dimensional maps of the ventricular and atrial chambers of the heart. Each point of these maps is annotated based on bioelectrical signals recorded from the electrodes located at the tip of the catheter. These maps are then used to guide catheter ablation within the heart. However, the electroanatomical mapping procedure results in relatively sparse sampling of the heart and a significant amount of time and skill are require to generate these maps. In this thesis, we present our software system for the integration of pre-operative, patient-specific magnetic resonance (MR) or computed tomography (CT) imaging data with real-time electroanatomical mapping (EAM) information.
(cont.) Following registration between the EAM and imaging data, the system allows for real-time catheter navigation within patient-specific anatomy. We then evaluate candidate registration strategies to rapidly and accurately align the pre-operative imaging data with the intra-operative mapping data using simulated electroanatomical mapping data using the great cardiac vessels including the aorta, superior vena cava, and coronary sinus. Based on these in vitro results, we focus on a registration strategy which is constrained by the ascending and descending aorta. In vivo prospective evaluation of the resulting image integration was then performed (n>200) in both experimental and clinical electrophysiology procedure. To compensate for residual error following registration or patient movement during a procedure, we present and evaluate warping strategies for deforming the pre-operative imaging data into agreement with the intra-operative mapping information.
by Zachary John Malchano.
M.Eng.
Leudar, Augustine Jan Seth Maranatha Bannatyne. "Integrating plant electrophysiology and sonic art." Thesis, Queen's University Belfast, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.727419.
Full textRoy, Thomas. "Time-Stepping Methods in Cardiac Electrophysiology." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32626.
Full textWang, Linwei. "Noninvasive imaging of 3D cardiac electrophysiology /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?ECED%202007%20WANGL.
Full textBlaetz, Taylor S. "The Electrophysiology of Written Informal Language." TopSCHOLAR®, 2015. http://digitalcommons.wku.edu/theses/1513.
Full textMorris, Andrew Paul. "The electrophysiology of mammalian salivary glands." Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279746.
Full textRakkah, N. I. A. "Electrophysiology of isolated mammalian spinal cord." Thesis, University of Southampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233185.
Full textChen, Tsai Yuan. "Network Electrophysiology Sensor-On-A- Chip." Digital WPI, 2011. https://digitalcommons.wpi.edu/etd-dissertations/389.
Full textZhang, Ke. "Cardiac electrophysiology and cardiotoxicity of halothane /." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487676261012213.
Full textGolas, Lillian B. "Mechanosensory neurons in culture : morphology and electrophysiology." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56638.
Full textTalbot, Hugo. "Interactive patient-specific simulation of cardiac electrophysiology." Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10056/document.
Full textThe objective of this thesis is to construct a training framework, allowing junior electrophysiologists to practice radio-frequency ablation for the treatment of ventricular arrhythmia on virtual patients. The first challenge consists in simulating the cardiac electrophysiology in real-time. A powerful GPU implementation is proposed to reach real-time performances. A realistic left bandle branch block can be simulated, thus inducing the associated late contraction of the left ventricle. For clinical application of electrophysiological mathematics, this GPU simulation needs to be personalized. This crucial step aims at adapting all model parameters in order to fit patient data. Our personalization is achieved in about 20 minutes and relies on an Unscented Kalman filter applied iteratively on the clinical data. Lastly, the construction of the first training framework dedicated to cardiac ablation is presented. An innovative multithreading approach couples the simulation of cardiac electrophysiology and catheter navigation. A clinical evaluation performed by electrophysiologists highlights the good performances and the realism of the training framework. This framework is a first step towards realistic and efficient virtual training systems in cardiology
Wetter, Spencer Ryan. "Olfactory psychophysics and electrophysiology in Huntington's Disease /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3083456.
Full textLeroy, Félix. "Atteinte différentielle de deux populations de motoneurones spinaux chez le souriceau SOD1 G93A (modèle de la maladie de Charcot)." Thesis, Paris 5, 2013. http://www.theses.fr/2013PA05T063/document.
Full textIn the second postnatal week, the locomotor behavior of mice changes from crawling to walking. This is made possible by profound changes in motor units. Yet, how the discharge properties of spinal motoneurons evolve during post-‐natal maturation and whether they have an effect on the motor unit maturation remains an open question. In neonates, the spinal motoneurons display two modes of discharge. For threshold pulses, 33% of the motoneurons have a discharge that start at the current onset and adapts during the pulse (“immediate firing motoneurons”). The remaining 66% motoneurons fire with a large delay and the discharge then accelerates throughout the pulse (“delayed firing motoneurons”). Though the delayed firing pattern is quite common in spinal motoneurons of neonates, the ionic mechanisms that elicit this mode of discharge have received little attention. Using the patch-clamp technique to record P6‐P10 mouse motoneurons in a spinal cord slice preparation, I characterized the ionic currents that underlie the delayed firing pattern. This is caused by a combination of an A-like potassium current that acts on a short time scale and a slow‐inactivating potassium current that delays the discharge on a much longer time scale. I then investigated how these two potassium currents contribute to the recruitment threshold and how they shape the F-I function of delayed motoneurons in neonatal mice. The slow inactivating potassium current induces memory effects that have a strong impact on motoneuron excitability and on its discharge. Building on these results, I tried to correlate the discharge pattern to known physiological sub‐types. The delayed firing motoneurons have a larger input conductance, a higher rheobase, a narrower action potential, a shorter AHP and a more complex dendritic arbor than the immediate firing motoneurons. Additionally, only a sub-‐population of the delayed firing motoneurons expressed the chondrolectin protein, a fast motoneuron marker. Based on this body of corroborating evidence, the immediate firing motoneurons would be slow type motoneurons whereas the delayed firing motoneurons would be fast type motoneurons. Finally, numerous electrical and geometrical abnormalities have been observed in spinal motoneurons of SOD1 G934 mice (model of the amyotrophic lateral sclerosis) during the second post-natal week but the results were somehow contradictory. In relation to the known differential sensitivity to the disease exhibited by slow and fast motoneurons, I investigated whether the immediate and delayed firing motoneurons are equally affected by the SOD1 mutation. This is not the case. I found that the SOD1 mutation induced a decrease in the rheobase and a hyperpolarization of the voltage threshold only in the immediate firing motoneurons, thereby making them more excitable than in WT mice. Furthermore, the dendrites of the immediate firing motoneurons are substantially shorter (about 35%) in the mutant than in the WT. In sharp contrast, the excitability of the delayed firing motoneurons is unchanged and the dendritic tree is nearly unaffected (the dendrites only undergo a 10% elongation). These results allow for reconsidering the link between hyperexcitability and degenerescence of the motoneurons
Fiancette, Jean-Francois. "Electrophysiologie multi-site et optogénétique appliquées à l’étude de corrélats neurobiologiques de l’addiction à la cocaïne chez le rat se comportant." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0901/document.
Full textDrug addiction is characterized by pathological drug seeking and taking, maintained despite their negative consequences. This is a chronic pathology, withdrawal attempts being unsuccessful in most cases. Cocaine addiction develops in about 15 to 20 % of habitual users. For cocaine, therapeutic options are lacking, which could be explained by the relatively poor understanding of the neurobiological mechanisms underlying cocaine addiction to date. Clinical and preclinical studies propose that addiction results from an imbalance between the cortical-subcortical circuits that process motivational value of drug-related stimuli versus those involved in cognitive inhibitory control. Hierarchical sequential changes in distinct, but interconnected circuits, including the basolateral amygdala, the nucleus accumbens and the prefrontal cortex could be at the core of pathological incentive processes and difficulty to control craving and drug taking. Studying addiction at the neuronal circuit level faces many challenges. Technically limited in humans, it can benefit from animal models, but only if they properly capture dimensions of the pathology. Over the last ten years, such models have been developed, but exclusively in rats. However, tools for a refined functional exploration of neuronal circuits have been established mostly in mice, and until recently they have begun to be explored in rats. In addition, another main challenge is the ability to investigate functional connectivity in real time in behaving animals. My thesis work had two objectives: 1. Studying markers of functional connectivity in rats showing a cocaine addiction-like behavior (Addict) or not (Non-addict). Our model of cocaine addiction allows identifying 15-20% of rats that show a high motivation for cocaine, a difficulty to limit drug seeking and that maintain drug taking despite negative consequences. These extreme behaviors occur after prolonged cocaine self-administration and despite that these rats have used a comparable amount of cocaine as compared to the others. In vivo, multi-site electrophysiology recordings, applied to single units or local field potentials, is a tool of choice for studying functional connectivity in rodents. A technical challenge has been to adapt and couple it to our model of cocaine addiction in the rat. We have evidenced significant differences in connectivity between Addict and Non-addict rats, which suggest a default of functionality of the medial prefrontal cortex in the Addict rats. 2. Studying the role of the prelimbic cortex (PL) in cocaine self-administration behavior in the rat. The canonical role of the PL in exclusively promoting drug seeking was recently questioned, with studies involving it also in inhibition of drug seeking. Our first goal was to clarify this role of the PL in early cocaine self-administration, i.e. before addiction-like behavior develops: understanding its early role to eventually compare it to its late role and whether an addiction-like behavior develops or not. We have shown that optogenetic PL inactivation can decrease or increase cocaine seeking in the same individual, according to experimental contingencies. PL neurons project to several remote structures. To study the role of these different neuronal pathways, we have worked in establishing optogenetic tools for the manipulation of specific neuronal pathways, in the rat, for which they are still poorly developed. My thesis work contribute, both theoretically and technically, to the understanding of the psychobiology of cocaine addiction
Li, Pan. "Multiscale Modelling of Mammalian Uterine and Cardiac Electrophysiology." Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491646.
Full textBroman, Daniel. "Lateralization of human olfaction : cognitive functions and electrophysiology." Doctoral thesis, Umeå : Department of Psychology, Umeå University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-861.
Full textSachse, Frank B. "Computational cardiology : modeling of anatomy, electrophysiology, and mechanics /." Berlin [u.a.] : Springer, 2004. http://www.loc.gov/catdir/enhancements/fy0818/2004104242-d.html.
Full textSaphier, D. J. "Electrophysiology and endocrine function of rat tuberoinfundibular neurones." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373694.
Full textCooper, Patricia J. "Stretch effects on cardiac electrophysiology : chronotropy and arrhythmogenesis." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442383.
Full textBrownson, Kathleen. "INVESTIGATION OF CARDIAC ELECTROPHYSIOLOGY IN HUMAN VENTRICULAR TISSUE." UKnowledge, 2014. http://uknowledge.uky.edu/cbme_etds/16.
Full textGrice, Sarah-Jane. "The electrophysiology of face perceptions in Williams Syndrome." Thesis, University College London (University of London), 2002. http://discovery.ucl.ac.uk/1317671/.
Full textKirby, Ian K. "Ticker-2 : a Qualitative Model of cardiac electrophysiology." Thesis, University of Aberdeen, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293110.
Full textConstantinescu, Mihaela. "Computer-assisted electroanatomical guidance for cardiac electrophysiology procedures." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/59668.
Full textOcholi, Ojonimi A. "An intracardiac navigation interface for electrophysiology modeling tools." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37083.
Full textIncludes bibliographical references (p. 79-81).
This thesis describes an interface that has been developed to assist in medical procedures. Several commercial systems are currently available each with their own strength and weaknesses and the goal of this interface is to leverage each of them. It is based upon a number of toolkits such as the Visualization Toolkit (VTK) and the GUI development tool QT. To facilitate the rapid deployment of highly modular applications, an Application Programming Interface (API) was created and modeled after the Model-View-Controller paradigm. The interface was then built using this API into an executable application and it provides various features such as accurate catheter navigation and the registration of data from different sources. In addition, the interface was used to investigate the accuracy of one commercial system (LocaLisa) with regards to another (CARTO).
by Ojonimi A. Ocholi.
M.Eng.and S.B.
Amos, D. P. "Effects of cannabinoids and novelty on hippocampal electrophysiology." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1335611/.
Full textWalmsley, John. "Incorporating inter-sample variability into cardiac electrophysiology simulations." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:6c653c3c-64e8-4337-bb97-728b99361573.
Full textMcManigle, John E. "Three-dimensional geometric image analysis for interventional electrophysiology." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:2f36fa8e-9c64-4807-97c0-25e63398da7e.
Full textMcNiven, Alistair Iain. "Electrophysiology of potassium channels in the hamster egg." Thesis, University of Edinburgh, 1989. http://hdl.handle.net/1842/29885.
Full textVaughan, Parker Andrew. "Electrophysiology of Optic Nerves in Methylglyoxal Treated Mice." Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1590769538838536.
Full textRobinson, Rebecca Louise. "Experimental study of electrophysiology using the fEITER system." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/experimental-study-of-electrophysiology-using-the-feiter-system(399260d4-6c11-4227-9633-4d76f933e5af).html.
Full textMatthews, Brian. "Micromachined planar patch-clamp system for electrophysiology research." Diss., Restricted to subscribing institutions, 2006. http://proquest.umi.com/pqdweb?did=1188879521&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Full textArzounian, Dorothée. "Sensory variability and brain state : models, psychophysics, electrophysiology." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCB055/document.
Full textThe same sensory input does not always trigger the same reaction. In laboratory experiments, a given stimulus may elicit a different response on each trial, particularly near the sensory threshold. This is usually attributed to an unspecific source of noise that affects the sensory representation of the stimulus or the decision process. In this thesis we explore the hypothesis that response variability can in part be attributed to measurable, spontaneous fluctuations of ongoing brain state. For this purpose, we develop and test two sets of tools. One is a set of models and psychophysical methods to follow variations of perceptual performance with good temporal resolution and accuracy on different time scales. These methods rely on the adaptive procedures that were developed for the efficient measurements of static sensory thresholds and are extended here for the purpose of tracking time-varying thresholds. The second set of tools we develop encompass data analysis methods to extract from electroencephalography (EEG) signals a quantity that is predictive of behavioral performance on various time scales. We applied these tools to joint recordings of EEG and behavioral data acquired while normal listeners performed a frequency-discrimination task on near-threshold auditory stimuli. Unlike what was reported in the literature for visual stimuli, we did not find evidence for any effects of ongoing low-frequency EEG oscillations on auditory performance. However, we found that a substantial part of judgment variability can be accounted for by effects of recent stimulus-response history on an ongoing decision
Tschabrunn, Michael Cory. "Electrophysiologic characterization of the arrhythmogenic substrate in re-entrant atrial and ventricular arrhythmias : insights from the clinical and experimental electrophysiology laboratories." Thesis, City, University of London, 2016. http://openaccess.city.ac.uk/17437/.
Full textDuchateau, Josselin. "Traitement et analyse du signal pour les arythmies ventriculaires." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0465/document.
Full textSignal processing tools are increasingly present in the electrophysiologist' s daily practice. These tools have the potential to enhance the detection of small electrical anomalies, and to enable the analysis of complex arrhythmia. Our work focuses on ventricular arrhythmia, and more specifically on how signal processing tech niques can help usbetter understand these diseases. lt is made up of three parts,focusing on different topics: uni-dimensional signal analysis (ECG and endocardial electrograms), non-invasive mapping, and invasive contact mapping. Concerning uni-dimensional signal analysis, we first propose a method to enhance the signal to noise ratio of ECG recordings. We use a combination of signal averaging and respiration gating to achieve this goal, and offer interesting perspectives for the detection of abnormal low amplitude potentials and non-invasive measurement of the HV interval. We then analyze the relationship between endocardial and ECG signais during ventricular fibrilla tion (VF) episodes. We demonstrate that endocardial and ECG dominant frequencies are similar,and that higher endocardial fragmentation results in a drop of the waveform amplitude on the surface ECG. Finally, we demonstrate through frequency domain analysis of 63 VF episodes a clear correlation between VF characteristics and clinical factors. Dominant frequency is particularly useful to dis criminate between different underlying causal substrates. We also demonstrate that VF characteris tics depend on the induction mode and induction site, in terms of dominant frequency, amount of fragmentation and ECG phase. Concerning non-invasive mapping, we compare different potential-based inverse problem resolution techniques. ECGi appears as one of the most reliable techniques. A clinical validation study of non-invasive ventricular activation mapping using ECGi isthen carried out. Fifty-five patients were included for whom non-invasive maps are compared to contact maps. We show a very poor overall correlation between non-invasive and invasive maps. Results are het erogeneous, with good correlation in patients with wide QRS activation patterns. Wethen propose different techniques to improve non-invasive activation mapping. A first study uses the surface laplacian and the gradient of the inverse-computed potential as inputs to activation map ping. A second study combines estimated delays between neighboring points and local activation time estimates to create a more globally coherent solution. Both studies demonstrate a significant improvement of activation maps. Concerning contact mapping, we first give an overview of interpolation domains and techniques that can be used to provide dense activation maps from sparse measures. We illustrate the influence of these techniques on the clinician's ability to make a correct diagnosis. We then use one of these interpolation techniques to create epicardial activation maps in Brugada patients. We show that these patients harbor epicardial electrical activity compatible with partial endo-epicardial conduction block. This phenomenon predominates in the right ventricular lateral wall and outflow tract. Finally,using an in silico model, we demonstrate the arrhythmogenic potential of such a dissociation. lnducibility peaks as the number of residual functional connections between endo and epicardium falls. ÜVERALL, our work uses signal processing techniques for different applications conceming ven tricular arrhythmia. We propose different methodological innovations that allow us to record and process cardiac electrical activity with increasing precision. Further progress is still required before non-invasive mapping can live up to its promises. The proposed methodological innovations can extend the use of electrocardiography and invasive mapping
Knecht, Sébastien. "Contribution à la compréhension des mécanismes électrophysiologiques de la fibrillation auriculaire et application pour le traitement invasif percutané." Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/241306.
Full textRoss, Patricia. "Electrophysiology of working memory, task modality and load effects." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ51224.pdf.
Full textDe, Roode Michael R. "The effects of Taurine depletion on rat heart electrophysiology /." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59626.
Full textRichards, Christopher David. "Electrophysiology and electrochemistry of substantia nigra neurones in vitro." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259895.
Full textSmith, P. A. "Electrophysiology of #beta#-cells form the islets of Langerhans." Thesis, University of East Anglia, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380117.
Full textRoche, Michael Geoffrey. "Electrophysiology of cortical spreading depression in the rat neocortex." Thesis, Boston University, 2012. https://hdl.handle.net/2144/12604.
Full textCortical spreading depression (CoSD) is a reaction of the cerebral cortex to injury and neuropathology. It is comprised of self propagating waves of neuronal hyperexcitability, followed by a pronounced and lasting depression of the electrical activity. This depression travels outward from the initiation source across the surface of the brain at a rate of 2-5 mm/min and is accompanied by a shift in the direct current potential. To better understand the mechanism behind CoSD, intra-cortical electrophysiological recording techniques were used to test the hypothesis that CoSD produces a layer-specific effect on the rat cortex. A linear multi-electrode was used to examine coherent neural activity at all levels of the primary visual cortex before, during and after CoSD. In addition, evoked neural activity was assessed by the use of paired pulse stimulation to the contralateral primary visual cortex. The effect of CoSD on the frequency content of the neural signals was also investigated. Finally, current source density analysis of the evoked signal was examined to determine whether CoSD produced alterations in the location or magnitude of where the evoked currents entered (current sinks) and left (current sources) the cortical laminae. CoSD was reliably induced, but the effects were short, only lasting for the first five minutes post initiation. Immediately following the initiation of CoSD, the first peak of the evoked potential was reduced, indicating that the excitability of the cortex was reduced by CoSD. After a period of time passed, the first peak returned to baseline while the second peak increased. The paired pulse index (ratio of the amplitude of the first evoked signal to the amplitude of the second evoked signal) was highly reduced and showed a lasting effect, indicating a reduction in the evoked inhibitory tone. This reduction in inhibitory tone was accompanied by alterations in the evoked gamma and beta bands, and a reduction in the alpha, which likely contributed in part to the reduction of the first peak. The spontaneous measured frequency bands showed a selective decrease in alpha, beta and theta, whereas gamma and delta were unaffected. All these were not specific to individual cortical lamina, but occurred at every laminae. Finally, current source density analysis showed that the CoSD did not induce any immediate or lasting changes in the pattern or magnitude of the current sinks and sources. These findings show that CoSD induces highly specific changes in the cortex, but does so in a uniform manner throughout the cortical width. The paired pulse data in conjunction with the results of the frequency analysis also suggests that CoSD causes a decrease in the efficacy of the cortical inhibitory networks. Frequency analysis further suggests that CoSD is possibly associated with a functional disconnection between the cortex and the thalamus. These data are the first to show the effects of CoSD using intracortical recordings and further the understanding of CoSD.
Bernstein, Jacob (Jacob Gold). "Development of extracellular electrophysiology methods for scalable neural recording." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/107581.
Full textCataloged from PDF version of thesis.
Includes bibliographical references.
In order to map the dynamics of neural circuits in mammalian brains, there is a need for tools that can record activity over large volumes of tissue and correctly attribute the recorded signals to the individual neurons that generated them. High-resolution neural activity maps will be critical for the discovery of new principles of neural coding and neural computation, and to test computational models of neural circuits. Extracellular electrophysiology is a neural recording method that has been developed to record from large populations of neurons, but well-known problems with signal attribution pose an existential threat to the viability of further system scaling, as analyses of network function become more sensitive to errors in attribution. A key insight is that blind-source separation algorithms such as Independent Component Analysis may ameliorate problems with signal attribution. These algorithms require recording signals at much finer spatial resolutions than existing probes have accomplished, which places demands on recording system bandwidth. We present several advances to technologies in neural recording systems, and a complete neural recording system designed to investigate the challenges of scaling electrophysiology to whole brain recording. We have developed close-packed microelectrode arrays with the highest density of recording sites yet achieved, for which we built our own data acquisition hardware, developed with a computational architecture specifically designed to scale to over several orders of magnitude. We also present results from validation experiments using colocalized patch clamp recording to obtain ground-truth activity data. This dataset provides immediate insight into the nature of electrophysiological signals and the interpretation of data collected from any electrophysiology recording system. This data is also essential in order to optimize probe development and data analysis algorithms which will one day enable whole-brain activity mapping.
by Jacob G. Bernstein.
Ph. D.
Canham, Amy Elizabeth. "Toward accessible evaluation of the electrophysiology of human vision." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/91431.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 75-77).
As photoreceptors in our retinas capture discrete photons, that energy is converted into an electrochemical signal which shoots back through the optic nerve and into our visual cortex. We can sample that signal as it's transmitted, by delivering specific stimuli and recording the aggregate response of the photoreceptors, but systems which accomplish this in current practice are out of reach for most ophthalmic clinics and completely unavailable to consumers. With a reimagined signal capture system and an optimized system design, I demonstrate a robust method for capturing the electrical signals emitted from the retina. With the improved accessibility and decreased cost of this technology, there are immediate opportunities for improved ophthalmic care on a broad scale. But beyond the clinical implications, accessible electroretinography presents an unprecedented opportunity for individuals to characterize their specific experience of color, contrast, and movement, making way for a whole new paradigm of tailored display technologies.
by Amy Elizabeth Canham.
S.M.
Panayiotou, Maria. "Motion gating for X-ray guided interventional electrophysiology procedures." Thesis, King's College London (University of London), 2015. http://kclpure.kcl.ac.uk/portal/en/theses/motion-gating-for-xray-guided-interventional-electrophysiology-procedures(70729d75-40ba-4886-b333-f5b1c5bf3556).html.
Full textAli, Rheeda. "Calibration of a personalised model of left atrial electrophysiology." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/48053.
Full textKhalbuss, Walid E. "Electrophysiology, Cell Calcium, and Mechanisms of Hepatocyte Volume Regulation." Digital Commons @ East Tennessee State University, 1990. https://dc.etsu.edu/etd/2709.
Full textTixier, Eliott. "Variability modeling and numerical biomarkers design in cardiac electrophysiology." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066325/document.
Full textThis PhD thesis is dedicated to the study of the variability observed in cardiac electrophysiology (i.e. the electrical activity of biological tissues) measurements and to the design of numerical biomarkers extracted from these measurements. The potential applications are numerous, ranging from a better understanding of existing electrophysiology models to the assessment of adverse effects of drugs or the diagnosis of cardiac pathologies. The cardiac electrophysiology models considered in the present work are either ODEs or PDEs depending on whether we focus on the cell scale or the tissue scale. In both cases, these models are highly non-linear and computationally intensive. We proceed as follows: first we develop numerical tools that address general issues and that are applicable beyond the scope of cardiac electrophysiology. Then, we apply those tools to synthetic electrophysiology measurements in various realistic scenarios and, when available, to real experimental data. In the first part of this thesis, we present a general method for estimating the probability density function (PDF) of uncertain parameters of models based on ordinary differential equations (ODEs) or partial differential equations (PDEs). The method is non-instrusive and relies on offline evaluations of the forward model, making it computationally cheap in practice compared to more sophisticated approaches. The method is illustrated with generic PDE and ODE models. It is then applied to synthetic and experimental electrophysiology measurements. In the second part of this thesis, we present a method to extract and select biomarkers from models outputs in view of performing classication tasks or solving parameter identification problems. The method relies on the resolution of a sparse optimization problem. The method is illustrated with simple models and then applied to synthetic measurements, including electrocardiogram recordings, and to experimental data obtained from micro-electrode array measurements