Download or read book Temporally Registered Optical Coherence Tomography and Fluorescence Microscopy for in Vitro Detection of Neural Activity written by Md Rezuanul Haque and published by . This book was released on 2014 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current methods for investigating activity in neurons largely rely on different varieties of electrodes, which require direct or very close contact, or fluorescence-based techniques, which require chemical or genetic introduction of a voltage- or calcium-sensitive fluorophore. The primary motivation for this work was to develop an intensity (non-phase) based extension of optical coherence tomography (OCT), an optical technology capable of rapid imaging of subsurface tissue structure with micrometer resolution without the need for exogenous contrast agents, for in vitro detection of neural activity. First, a preliminary study of epileptiform activity in murine hippocampal brain slices was used as an assessment of OCT for in vitro detection of neural activity. Elevated potassium was used to induce seizure-like bursts of activity. Decreases in OCT light intensity were found to be correlated with the initial onset of large-scale activation using simultaneous electrophysiological detection with a multi-electrode array. These results motivated the development of a novel spatiotemporally co-registered OCT and fluorescence microscopy (FM) system capable of observing neural activity simultaneously with both modalities. The combined system was designed to provide sequential OCT volumetric imaging over an extended depth range with fluorescence imaging through a common objective. This allows for the results of analytical methods developed to endogenously detect neural activity based on OCT intensity to be correlated with changes in fluorescence. Finally, the system was used to observe neural circuitry in the brain of Drosophila pupae. The fluorescence response of GCaMP-3 labeled bursicon and kinin cells in response to presentation of ecdysis triggering hormone (ETH) is well-characterized. Time sequences of OCT volumetric data acquired over these neurons in in vitro adolescent Drosophila brain in response to presentation of ETH were analyzed and compared to simultaneously recorded fluorescence data. Changes in the backscattered OCT intensity in both cell types were found to correlate well with neural activity as identified by fluorescence. These results demonstrate the potential of OCT for in vitro detection of neural activity without the need for fluorescence contrast.
Download or read book Progress Towards Detecting Neural Activity in Optical Coherence Tomography Using Phase written by Jasmine Kavan Shah and published by . This book was released on 2017 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical Coherence Tomography (OCT) is non-invasive, real time optical imaging method based on low coherence interferometry with high resolution. It is capable of imaging microstructure by measuring the light backscattered from the sample. Under the AGI grant, I have built a Swept Source OCT (SS-OCT) / phase resolved OCT to detect the nanometer(nm) scale changes in the cell membrane that occur during membrane depolarization and Ion influx. This type of small changes can be seen using phase. Intensity is robust but is less sensitive to the small-scale changes whereas phase is highly sensitive. The noise level for phase difference quantification depends on the lateral motion, triggering of the wavelength mismatch and signal to noise ratio (SNR). To detect the nm scale changes phase noise should be minimum. The phase noise is inversely proportional to SNR. The SNR of the system should be maximum. The SS-OCT has swept source with sweep rate 100 kHz and it is not phase stable. It needs post processing algorithm to match the triggering wavelength to stabilize the phase. I wrote the code in GPU to reduce the computation time for post processing algorithm. Due to a few setbacks related to moving the system to a collaborating lab, the biological portion of my thesis work, trying to find the neural activity in the walking leg nerve of the Lobster using phase, was done with a spectral domain OCT (SD-OCT). To see any action potential change in the nerve I realigned the SD-OCT system with center wavelength to increase the SNR of the system and the sample arm with the nerve chamber (3D printed) to stimulate the nerve at one end and take the OCT image at the other end to see the action potential.
Download or read book Quantification of Changes of Intensity and Attenuation Coefficient During Neural Activity Using Optical Coherence Tomography written by Md. Monirul Hasan and published by . This book was released on 2018 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: The nervous system, which receives information through the electrical signal to coordinate and disseminate information about the body and its environment, is an assembly of neurons. Current methods of detection of neural activity are based on electrophysiology, which requires direct or near direct contact, or fluorescence-based techniques, which require the introduction of reporter molecules, raising a concern of toxicity. Optical coherence tomography (OCT) detects neural activity by taking advantage of intrinsic structural changes that accompany neural activity without any exogenous agents. The phase-resolved OCT detected 10-30 nm swelling of axon during neural activity from the functionally stimulated compound eye of the horseshoe crab (limulus) by utilizing the phase-resolved measurement. There was a decrease of backscattered intensity during propagation of action potential due to change of scattering as well. Further study on in vitro murine brain slice showed the changes of the phase (or thickness change) as well as a decrease of back-reflected intensity during propagation of action potential. Above studies with pr-OCT were performed without scanning because scanning introduced phase noise, and the desired signal was buried under noise for the signal to noise ratio of 25~30 dB. However, spectral domain OCT was used to capture 3D volumetric intensity images during the neural activity in in vitro seizure mouse model after a period of baseline data. The average intensity of the hippocampal brain slice decreased by 10~18% from baseline during neural activity. Although intensity can separate neural activity from non-neural activity with 97.27% specificity and 97.60% sensitivity, it varies from experiment to experiment. Attenuation coefficient (μ), which quantifies how strongly a sample scatters and absorbs light is a constant for a sample, can solve the problem. During neural activities, there was a 10~15% decrease of μ. For both intensity and μ based method, there was a spatial correlation between optical changes and gold standard electrophysiology. Finally, quantified OCT intensity detected a localized action potential from CA1 of the hippocampal brain slice during ripple activation and -1% intensity threshold separated activity from non-activity.
Download or read book Coded Computational Illumination and Detection for Three dimensional Fluorescence Microscopy written by Samuel J. Yang and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In vivo calcium imaging enables the optical monitoring of neural activity at the level of individual neurons in real time, necessitating the development of high speed, three-dimensional (3D) fluorescence microscopy techniques with at least single-neuron spatial resolution. Because a typical widefield microscope intrinsically produces only two-dimensional images, various illumination and detection coding strategies have been implemented to address the challenge of 3D fluorescence microscopy, utilizing either precisely structured and temporally scanned illumination patterns, such as in two-photon laser scanning microscopy or coding of the emission, as in light field microscopy, respectively. However, many single-focal illumination coding strategies have limited acquisition speeds, while detection-coding-only strategies requiring computational reconstruction of the 3D volume are limited by optical aberrations of the tissue. We present a 3D calcium imaging approach utilizing both multifocal scanned two-photon laser excitation for illumination coding and detection coding with the light field microscopy approach suitable for in vivo mammalian calcium imaging. A holographic 3D multifocal illumination pattern is targeted only towards pre-localized neurons avoiding the unnecessary illumination of other regions. The resulting fluorescence emission is coded and detected on an image sensor and deconvolution is used to recover the neural activity at each site. We present the design and optimization of such an imaging strategy, and validate the approach with experimental measurements. Finally, we demonstrate the application of this approach to in vivo mouse calcium imaging. The design and implementation of another technique, frame-projected independent fiber photometry, enabling the optical recording and control of neural activity in freely moving mammals with region-level spatial resolution, is presented in a dedicated chapter as well, including simultaneous recording from multiple brain regions in a mouse during social behavior, two-color activity recording, and optical optogenetic stimulation eliciting dynamics matching naturally observed patterns.
Download or read book High Resolution Imaging in Microscopy and Ophthalmology written by Josef F. Bille and published by Springer. This book was released on 2019-08-13 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book provides a comprehensive overview of the application of the newest laser and microscope/ophthalmoscope technology in the field of high resolution imaging in microscopy and ophthalmology. Starting by describing High-Resolution 3D Light Microscopy with STED and RESOLFT, the book goes on to cover retinal and anterior segment imaging and image-guided treatment and also discusses the development of adaptive optics in vision science and ophthalmology. Using an interdisciplinary approach, the reader will learn about the latest developments and most up to date technology in the field and how these translate to a medical setting. High Resolution Imaging in Microscopy and Ophthalmology – New Frontiers in Biomedical Optics has been written by leading experts in the field and offers insights on engineering, biology, and medicine, thus being a valuable addition for scientists, engineers, and clinicians with technical and medical interest who would like to understand the equipment, the applications and the medical/biological background. Lastly, this book is dedicated to the memory of Dr. Gerhard Zinser, co-founder of Heidelberg Engineering GmbH, a scientist, a husband, a brother, a colleague, and a friend.
Download or read book Phase Resolved Optical Coherence Tomography for Label free Detection of Neural Activity written by Minh Quang Tong and published by . This book was released on 2018 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current methods for detection of nervous system activity have been limited to electrophysiology, which requires the electrode to contact the nervous system or optical-based techniques that require incorporation of reporter agents. Both methods are golden standards but have limitations. Optical coherence tomography (OCT) is an imaging technique based on light that measures intrinsic structural changes associated with an action potential. A benefit of using OCT is that it does not require any exogenous agents and is minimally invasive. Phase-resolved OCT detects 1-30 nm swelling of an axon during neural activity. In my studies described here, phase-resolved OCT was used to detect the swelling Drosophila neurons when presented with ecdysis triggering hormone as well as a 1-3 nm swelling of a cockroach axon caused by action. However, since phase imaging is limited to one point, the dissertation ends with development of the line field swept source OCT system that can provide images of a b-line or cross-sectional image without using a scanning device.
Download or read book Fluorescence Lifetime Imaging Ophthalmoscopy written by Martin Zinkernagel and published by Springer. This book was released on 2019-07-29 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the emerging non-invasive imaging technique of Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO). FLIO reveals unique information on retinal diseases, ranging from age-related macular degeneration and vascular diseases to hereditary retinal dystrophies. Fluorescence lifetimes enable the evaluation of disease progression before irreversible structural changes occur. The image acquisition is suitable for diagnostic purposes and follow-up examinations to investigate the natural course of disease, and to monitor the effects of possible therapies. This book fills the gap between available literature and gives state-of-the-art guidance on the principles of the FLIO technique, image acquisition, and data analysis. Written by a team of expert leaders within this field, this book will be relevant for scientists and clinicians with an interest in ophthalmoscopy.
Download or read book Optical Coherence Tomography written by Wolfgang Drexler and published by Springer Science & Business Media. This book was released on 2008-12-10 with total page 1346 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical coherence tomography (OCT) is the optical analog of ultrasound imaging and is emerging as a powerful imaging technique that enables non-invasive, in vivo, high resolution, cross-sectional imaging in biological tissue. This book introduces OCT technology and applications not only from an optical and technological viewpoint, but also from biomedical and clinical perspectives. The chapters are written by leading research groups, in a style comprehensible to a broad audience.
Download or read book Index Medicus written by and published by . This book was released on 2002 with total page 1948 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book OCT and Imaging in Central Nervous System Diseases written by and published by . This book was released on 2020 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of OCT and Imaging in Central Nervous System Diseases offers updated state-of-the-art advances using optical coherence tomography (OCT) regrading neuronal loss within the retina. Detailed information on the OCT imaging and interpretation is provided for the evaluation of disease progression in numerous neurodegenerative disorders and as a biological marker of neuroaxonal injury. Covering disorders like multiple sclerosis, Parkinson's disease, Alzheimer's disease, intracranial hypertension, Friedreich's ataxia, schizophrenia, hereditary optic neuropathies, glaucoma, and amblyopia, readers will given insights into effects on the retina and the and optic nerve. Individual chapters are also devoted to OCT technique, new OCT technology in neuro-ophthalmology, OCT and pharmacological treatment, and the use of OCT in animal models. Similar to the first edition, this book is an excellent and richly illustrated reference for diagnosis of many retinal diseases and monitoring of surgical and medical treatment. OCT allows to study vision from of the retina to the optic tracts. Retinal axons in the retinal nerve fiber layer (RNFL) are non-myelinated until they penetrate the lamina cribrosa. Hence, the RNFL is an ideal structure for visualization of any process of neurodegeneration, neuroprotection, or regeneration. By documenting the ability of OCT to provide key information on CNS diseases, this book illustrates convincingly that the eye is indeed the "window to the brain".
Download or read book Make Life Visible written by Yoshiaki Toyama and published by Springer Nature. This book was released on 2019-10-02 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book describes marked advances in imaging technology that have enabled the visualization of phenomena in ways formerly believed to be completelyimpossible. These technologies have made major contributions to the elucidation of the pathology of diseases as well as to their diagnosis and therapy. The volume presents various studies from molecular imaging to clinical imaging. It also focuses on innovative, creative, advanced research that gives full play to imaging technology inthe broad sense, while exploring cross-disciplinary areas in which individual research fields interact and pursuing the development of new techniques where they fuse together. The book is separated into three parts, the first of which addresses the topic of visualizing and controlling molecules for life. Th e second part is devoted to imaging of disease mechanisms, while the final part comprises studies on the application of imaging technologies to diagnosis and therapy. Th e book contains the proceedings of the 12th Uehara International Symposium 2017, “Make Life Visible” sponsored by the Uehara Memorial Foundation and held from June 12 to 14, 2017. It is written by leading scientists in the field and is an open access publication under a CC BY 4.0 license.
Download or read book Optical Coherence Tomography in Multiple Sclerosis written by Axel Petzold and published by Springer. This book was released on 2018-02-21 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives a clinical context to optical coherence tomography (OCT) findings, while considering the differential diagnosis and providing patient management guidance. Relevant anatomical and technical aspects are discussed, followed by a pragmatic illustration of the use of OCT for the clinical spectrum of multiple sclerosis and optic neuritis, and finishing with information on monitoring ocular side effects of recently approved disease-modifying treatments in multiple sclerosis. Optical Coherence Tomography in Multiple Sclerosis: Clinical Applications is aimed at clinical neurologists working with patients suffering from MS and general neurologists who see patients with visual symptoms in their daily practice. Ophthalmologists sharing clinical responsibilities with neurologists for patients under disease-modifying treatments will also find the book of interest.
Download or read book Optical Coherence Tomography and Its Non medical Applications written by Michael Wang and published by BoD – Books on Demand. This book was released on 2020-05-27 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical coherence tomography (OCT) is a promising non-invasive non-contact 3D imaging technique that can be used to evaluate and inspect material surfaces, multilayer polymer films, fiber coils, and coatings. OCT can be used for the examination of cultural heritage objects and 3D imaging of microstructures. With subsurface 3D fingerprint imaging capability, OCT could be a valuable tool for enhancing security in biometric applications. OCT can also be used for the evaluation of fastener flushness for improving aerodynamic performance of high-speed aircraft. More and more OCT non-medical applications are emerging. In this book, we present some recent advancements in OCT technology and non-medical applications.
Download or read book OCT Angiography in Retinal and Macular Diseases written by F. Bandello and published by Karger Medical and Scientific Publishers. This book was released on 2016-03-21 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: In only a short period of time, the innovative procedure of OCT angiography has become an essential macula imaging technique. Now that it is routinely used in clinical practice, the investigation of retinal and choroidal circulation is non-invasive, which significantly changes the professional’s approach to patients. In this volume, retina specialists and renowned experts share their experience with OCT angiography. They have included numerous color images and presented current ideas to form a base for further research and discussion. This book provides retina specialists, ophthalmologists, and researchers with a first glance at original research and clinical reports on this new methodology.
Download or read book Handbook of Biomedical Fluorescence written by Mary-Ann Mycek and published by CRC Press. This book was released on 2019-07-17 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: Melding basic and clinical science, this reference provides a comprehensive overview of the roles that biophysics, photochemistry, and computational modeling play in the biomedical applications of fluorescence spectroscopy and imaging. Penned by pioneering researchers, the Handbook of Biomedical Fluorescence discusses fundamental aspects of fluorescence generation in organic molecules within tissue, theoretical and experimental views of how light propagation in tissue can be used to interpret fluorescence signals, endogenous and exogenous fluorescence agents in medical or basic research studies, and radiation transport, diffusion theory, and the Monte Carlo method.
Download or read book Handbook of Full Field Optical Coherence Microscopy written by Arnaud Dubois and published by CRC Press. This book was released on 2016-10-14 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt: Full-field optical coherence microscopy (FF-OCM) is an imaging technique that provides cross-sectional views of the subsurface microstructure of semitransparent objects. The technology is based on low-coherence interference microscopy, which uses an area camera for en face imaging of the full-field illuminated object. FF-OCM benefits from the lateral imaging resolution of optical microscopy along with the capacity of optical axial sectioning at micrometer-scale resolution. The technique can be employed in diverse applications, in particular for non-invasive examination of biological tissues. This handbook is the first to be entirely devoted to FF-OCM. It is organized into four parts with a total of 21 chapters written by recognized experts and major contributors to the field. After a general introduction to FF-OCM, the fundamental characteristics of the technology are analyzed and discussed theoretically. The main technological developments of FF-OCM for improving the image acquisition speed and for endoscopic imaging are presented in part II. Extensions of FF-OCM for image contrast enhancement or functional imaging are reported in part III. The last part of the book provides an overview of possible applications of FF-OCM in medicine, biology, and materials science. A comprehensive compilation of self-contained chapters written by leading experts, this handbook is a definitive guide to the theoretical analyses, technological developments, and applications of FF-OCM. Using the rich information the book is replete with, a wide range of readers, from scientists and physicists to engineers as well as clinicians and biomedical researchers, can get a handle on the latest major advances in FF-OCM.
Download or read book Visualizing Chemistry written by National Research Council and published by National Academies Press. This book was released on 2006-06-01 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scientists and engineers have long relied on the power of imaging techniques to help see objects invisible to the naked eye, and thus, to advance scientific knowledge. These experts are constantly pushing the limits of technology in pursuit of chemical imagingâ€"the ability to visualize molecular structures and chemical composition in time and space as actual events unfoldâ€"from the smallest dimension of a biological system to the widest expanse of a distant galaxy. Chemical imaging has a variety of applications for almost every facet of our daily lives, ranging from medical diagnosis and treatment to the study and design of material properties in new products. In addition to highlighting advances in chemical imaging that could have the greatest impact on critical problems in science and technology, Visualizing Chemistry reviews the current state of chemical imaging technology, identifies promising future developments and their applications, and suggests a research and educational agenda to enable breakthrough improvements.
