Дисертації з теми "Intrinsic optical signal imaging"
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Berwick, Jason. "Investigation of the V-signal oscillation using intrinsic optical imaging and imaging spectroscopy and its relevance to cortical metabolism." Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312793.
Повний текст джерелаHarel, Noam. "Functional organization of auditory cortex revealed by optical imaging of intrinsic signals." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0025/NQ49983.pdf.
Повний текст джерелаLabron, Mark William. "Imaging the effects of acute osmotic stress on the rat neocortical slice using intrinsic optical signals and calcein fluorescence." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ36047.pdf.
Повний текст джерелаXu, Wei. "Analog Signal Processing for Optical Coherence Imaging Systems." Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/195225.
Повний текст джерелаRaguet, Hugo. "A Signal Processing Approach to Voltage-Sensitive Dye Optical Imaging." Thesis, Paris 9, 2014. http://www.theses.fr/2014PA090031/document.
Повний текст джерелаVoltage-sensitive dye optical imaging is a promising recording modality for the cortical activity, but its practical potential is limited by many artefacts and interferences in the acquisitions. Inspired by existing models in the literature, we propose a generative model of the signal, based on an additive mixtures of components, each one being constrained within an union of linear spaces, determined by its biophysical origin. Motivated by the resulting component separation problem, which is an underdetermined linear inverse problem, we develop: (1) convex, spatially structured regularizations, enforcing in particular sparsity on the solutions; (2) a new rst-order proximal algorithm for minimizing e›ciently the resulting functional; (3) statistical methods for automatic parameters selection, based on Stein’s unbiased risk estimate.We study thosemethods in a general framework, and discuss their potential applications in variouselds of applied mathematics, in particular for large scale inverse problems or regressions. We develop subsequently a soŸware for noisy component separation, in an integrated environment adapted to voltage-sensitive dye optical imaging. Finally, we evaluate this soŸware on dišerent data set, including synthetic and real data, showing encouraging perspectives for the observation of complex cortical dynamics
R, S. Umesh. "Algorithms for processing polarization-rich optical imaging data." Thesis, Indian Institute of Science, 2004. http://hdl.handle.net/2005/96.
Повний текст джерелаBrookshire, Charles Thomas. "Illumination Recovery For Optical Microscopy." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1588936914060945.
Повний текст джерелаKoh, P. H. "Methodology of optical topography measurements for functional brain imaging and the development and implementation of functional optical signal analysis software." Thesis, University College London (University of London), 2007. http://discovery.ucl.ac.uk/1444898/.
Повний текст джерелаBalu, Ramani. "Intrinsic and Synaptic Properties of Olfactory Bulb Neurons and Their Relation to Olfactory Sensory Processing." Case Western Reserve University School of Graduate Studies / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=case1173540900.
Повний текст джерелаMartin, Phillip A., and Phillip A. Martin. "Investigation of the Feasibility of an Optical Imaging System for the Application of In Vivo Flow Cytometry." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/621197.
Повний текст джерелаWang, Zhipeng. "A framework for the Analysis and Evaluation of Optical Imaging Systems with Arbitrary Response Functions." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/195108.
Повний текст джерелаLanger, Dominik, 't Hoff Marcel van, Andreas J. Keller, Chetan Nagaraja, Oliver A. Pfaeffli, Maurice Goeldi, Hansjoerg Kasper, and Fritjof Helmchen. "HelioScan : A software framework for controlling in vivo microscopy setups with high hardware flexibility, functional diversity and extendibility." Uppsala universitet, Genetisk utvecklingsbiologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-201813.
Повний текст джерелаPaid Open Access
Adya, Vandana. "Detection of Signal Parameters and Backscattering Polarimetric Imaging Signatures using Molecular Optical Contrast Agents and Preclinical Liquid Phantoms." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1225204620.
Повний текст джерелаKhan, Sajjad. "Liquid Crystal Optics for Communications, Signal Processing and 3-D Microscopic Imaging." Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3389.
Повний текст джерелаPh.D.
Optics and Photonics
Optics
Morel, Sophie. "Imagerie grand champ en anatomopathologie." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY075/document.
Повний текст джерелаThis PhD project aims to develop a simple, fast (35 minutes), wide-field (up to 2.5 cm x 2.5 cm) multiscale (µm-cm) imaging method for stained and unstained tissue slides for digital pathology application. We present a solution based on lensfree imaging. It is a simple, low-cost technique that enables wide field imaging (10-30 mm²) of sparse objects, like viruses, bacteria or cells. In this project, we adapted lensfree imaging for dense objects observation, like stained or unstained tissue slides. The sample is illuminated under multiple illumination wavelengths, and a new multiwavelength holographic reconstruction algorithm was developed in order to reconstruct the modulus and phase of dense objects. Each image covers 10 mm² field of view, and is reconstructed in 1.1 second. An image of the whole tissue slide covers 6.25 cm². It is recorded in 35 minutes by scanning the sample over the sensor. The reconstructed images are multiscale, allowing the user to observe the overall tissue structure and to zoom down to the single cell level (3-4 µm). The method was tested on various stained and unstained pathology samples. Besides tissue slides, multiwavelength lensfree imaging shows encouraging results for meningitis diagnosis, bacteria population monitoring for identification and antibiotic susceptibility testing, and cell culture monitoring
Akin, Ryan E. "Minimally invasive assessment of lymphatic pumping pressure using near infrared imaging." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47536.
Повний текст джерелаQureshi, Muhammad Shakeel. "Integrated front-end analog circuits for mems sensors in ultrasound imaging and optical grating based microphone." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29613.
Повний текст джерелаCommittee Chair: Hasler, Paul; Committee Co-Chair: Degertekin, Levent; Committee Member: Anderson, David; Committee Member: Ayazi, Farrokh; Committee Member: Brand, Oliver; Committee Member: Hesketh, Peter. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Zenteno, Omar. "Markerless tracking of a fiber-optical probe by endoscopic vision : Towards multispectral enhanced biopsy." Thesis, Orléans, 2020. https://theses.univ-orleans.fr/public/2020ORLE3181_va.pdf.
Повний текст джерелаThis work addresses the problem of bi-modal registration to provide the surgeon with an accurate optical biopsy location in endoscopic frames during image guided examination. A multispectral-augmented endoscopic prototype was developed based on a commercial endoscopic system: A fiberscope is inserted into the operating channel and connected to a snapshot multispectral camera (41 bands in the range of 470 to 975 nm), working as a localized optical biopsy for a complementary medical exploration with a much smaller field of view. The registration between modalities is challenging due to the lack of texture in gastric wall which causes direct image-content registration methods to fail. Therefore, we approach the registration problem as a relative pose estimation between two non-homogeneous cameras (endoscope and fiberscope) not rigidly linked. Both cameras can be separately calibrated using a chessboard pattern so their instantaneous relative pose can be estimated by tracking the moving camera (fiberscope). To do this, we take advantage of the fiberscope presence in the endoscopic images and its geometry. Therefore, the pose of the fiberscope is estimated by minimizing the re-projection error of a virtual cylinder using a predicted pose in four steps: (i) the segmentation of the fiberscope is achieved through CNNs models trained on our endoscopic sequences;(ii) a 3D cylinder axis is initialized using the initial segmentation and Plücker’s coordinates;(iii) the pose estimate is optimized by maximizing Jaccard’s similarity index between an automatic segmentation of the fiberscope in the image and the virtual cylinder projection in the endoscopic reference frame; (iv) we use the pose of both cameras to estimate the transformation through direct homography between virtually projected points achieving a markerless tracking. This approach was validated using a virtual framework to realistically simulate the movements of the fiberscope inside the operating channel (i.e, insertion and precession) and in-vivo sequences acquired with our multimodal prototype in a medical center. The final registered images offer the surgeon real time visualization of the area targeted by the fiberscopeat the gastric wall and its corresponding spectral data. In an off-line process, it is also possible to locate the hyperspectral biopsy on a panoramic map constructed by image mosaicing techniques from the endoscopic video acquired during examination. In a general way, the proposed method for locating optical biopsy can be extended to any type of imaging, specially in the presence of poorly textured images or when markerless probe tracking is necessary, and could be valuable for patient monitoring
Elsner, Mark Michael. "Analyse epileptischer Aktivität anhand intrinsischer optischer Signale und elektrophysiologischer Methoden in vitro nach Status epilepticus in vivo." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2004. http://dx.doi.org/10.18452/15146.
Повний текст джерелаThe development of chronic epilepsy is a serious consequence of Status epilepticus. Little is known about the mechanisms and kinetic of the epileptogenic process. The aim of this md-thesis was the analysis of localisation and kinetic of functional deficits in vitro after Status epilepticus in vivo. Using the Low-Magnesium-Model, seizure-like events (SLE) were induced in combined hippocampal-entorhinal cortex slices of wistar rats after electrically induced self-sustaining Status epilepticus (SSSE). One, four and eight weeks after SSSE the in-vitro-analysis of SLE was performed. In order to determine onset and spread-pattern of epileptic activity, the measurement of the extracellular field-potential was combined with the imaging of intrinsic optical signals (IOS). In the time course after SSSE there was a reduction of the latency to onset of seizure activity and an increase of the SLE-frequency. Four and eight weeks after SSSE a significant increase of SLE with regional onset was found. In Addition, there was an increase of non-contiguous propagation of seizure activity. Eight weeks after SSSE 50% of the brain-slices showed autonomous high-frequent activity in the dentate gyrus. In conclusion a reduction of the latency to onset of seizure activity and an increase of the SLE-frequency were found. These changes are indicators of increased excitability after SSSE. Other than the regional onset, the non-contiguous spread-pattern also indicates increased synchronicity of the neuronal network after SSSE. The autonomous activity in the dentate Gyrus shows, that the previously described structural changes in this region lead to functional deficits.
Hallum, Luke Edward Graduate School of Biomedical Engineering Faculty of Engineering UNSW. "Prosthetic vision : Visual modelling, information theory and neural correlates." Publisher:University of New South Wales. Graduate School of Biomedical Engineering, 2008. http://handle.unsw.edu.au/1959.4/41450.
Повний текст джерелаLindberg, Arvid. "Development of rigid polarimetric endoscope for early detection of cancer in vivo." Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX010.
Повний текст джерелаEarly diagnosis of a cancerous lesion and complete surgical resection of the diseased areas are both crucial points in order to greatly improve the chances for recovery of a patient. However, early detection of cancer is a very difficult task. It relies on random biopsies of suspicious areas which are not easy to identify at this stage of the disease using conventional imaging techniques (visible imaging, ultrasound, magnetic resonance, X-ray scanner, positron emission tomography). In addition, the correct evaluation of surgical resection margins remains often very difficult or even impossible in some cases.Polarimetric imaging is a promising technique for the early detection of cancerous lesions on the surface of the organs and for a better definition of the resection limits during surgery. Biomedical research activity, conducted within the 'Applied Optics and Polarimetry' team of the LPICM, focuses on the development of Mueller polarimetric imaging systems for improving the management of epithelial cancers, also known as carcinomas, which represent 80-90% of all cancers. In this regard the LPICM leads a project funded by the “Institut National du Cancer (INCa)”, on the use of Mueller polarimetric imaging for improving the management of cervical cancer at different stages of its evolution. At present an extensive series of ex vivo measurements is in progress in three different hospitals of Paris (Institut Gustave Roussy, Kremlin Bicêtre and Institut Mutualiste Montsouris). The final goal of this study is to evaluate the performance of Mueller polarimetric imaging technique in terms of sensitivity and specificity, while using an interpretation of corresponding histology slides by pathologists as a “golden standard” of cancer diagnostics. Ex vivo measurements provide a precise knowledge of the systematic effects which can negatively affect image quality. Hence, the results of this study represent a good starting point for in vivo applications of polarimetric imaging technique. Within the frame of INCa project the analysis of uterine cervix in vivo is planned, using a classical colposcope modified to obtain polarimetric Mueller images.The endoscope is another medical instrument used also to detect cancerous or precancerous lesions in the internal cavities of human body (esophagus, colon, rectum, etc.). The proposed thesis subject consists in developing a Mueller polarimetric rigid endoscope and evaluating its performance in terms of sensitivity and specificity. The work of PhD student will be concerned with instrumentation in optics, acquisition of data, signal processing and statistical evaluation of the performance of technique. Thus, the subject of this thesis is on the interface between physics and medical diagnostics and it shows a strong potential for industrial development with a significant societal impact
Yoo, Thomas. "Application of a Multimodal Polarimetric Imager to Study the Polarimetric Response of Scattering Media and Microstructures." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX106/document.
Повний текст джерелаThe work carried out during this thesis was aimed to study the interaction of polarized light from the scattering media and particles. This work is part of a strong collaborative context between the LPICM and various private and public laboratories. A wide variety of aspects have been treated deeply, including instrumental development, advanced numerical simulation and the creation of measurement protocols for the interpretation of complex data.The instrumental part of the thesis was devoted to the development of an innovative instrument, suitable for taking polarimetric images at different scales (from millimeters to microns) that can be quickly reconfigured to offer different imaging modes of the same sample. The two main aspects that characterize the instrument are i) the possibility of obtaining real polarimetric images of the sample and the angular distribution of light scattered by an illuminated zone whose size and position can be controlled, ii) the total control of the polarization state, size and divergence of the beams. These two aspects are not united on any other commercial or experimental apparatus today.The first object of the study using the multimodal imaging polarimeter was to study the effect of the thickness from a scattering medium on its optical response. In medical imaging, there is a broad consensus on the benefits of using different polarimetric properties to improve the effectiveness of optical screening techniques for different diseases. Despite these advantages, the interpretation of the polarimetric responses in terms of the physiological properties of tissues has been obscured by the influence of the unknown thickness of the sample.The objective of the work was, therefore, to better understand the dependence of the polarimetric properties of different scattering materials with the known thickness. In conclusion, it is possible to show that the polarimetric properties of the scattering media vary proportionally with the optical path that the light has traveled inside the medium, whereas the degree of polarization depends quadratically on the optical path. This discovery could be used to develop a method of data analysis that overcomes the effect of thickness variations, thus making the measurements very robust and related only to the intrinsic properties of the samples studied.The second object of study was to study the polarimetric responses from particles of micrometric size. The selection of the particles studied by analogy to the size of the cells that form the biological tissues, and which are responsible for the dispersion of light. By means of the polarimetric measurements, it has been discovered that when the microparticles are illuminated with an oblique incidence with respect to the optical axis of the microscope, they appear to behave as if they were optically active. Moreover, it has been found that the value of this apparent optical activity depends on the shape of the particles. The explanation of this phenomenon is based on the appearance of a topological phase of the beam. This topological phase depends on the path of the light scattered inside the microscope. The unprecedented observation of this topological phase has been done by the fact that the multimodal polarimetric imager allows illumination of the samples at the oblique incidence. This discovery can significantly improve the efficiency of optical methods for determining the shape of micro-objects
Witomski, Arnaud. "Imagerie laser à synthèse d'ouverture par réinjection optique." Phd thesis, Grenoble 1, 2007. http://tel.archives-ouvertes.fr/tel-00144904.
Повний текст джерелаNous présentons ensuite dans ce mémoire le dispositif LOFI en régime paramétrique soumis à une modulation de pompage. Nous présentons l'analyse d'un laser soumis de manière synchronisée à une réinjection optique décalée en fréquence et une modulation de pompage et nous montrons qu'il est possible d'amplifier paramétriquement le signal rétrodiffusé par la cible. Nous validons cette analyse par des résultats numériques et expérimentaux et nous démontrons qu'il est possible de déterminer la quantité de lumière réinjectée dans le laser.
Fredenberg, Erik. "Spectral Mammography with X-Ray Optics and a Photon-Counting Detector." Doctoral thesis, KTH, Medicinsk avbildning, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11641.
Повний текст джерелаQC 20100714
Turley, Jordan Alexander. "An analysis of signal processing techniques for intrinsic optical signal brain imaging." Thesis, 2018. http://hdl.handle.net/1959.13/1383963.
Повний текст джерелаIntrinsic Optical Signal (IOS) imaging uses light in the visible spectrum to visualise activity related changes within the cerebral cortex. A limiting issue with IOS is the presence of large disturbance components. Appropriate signal processing is therefore important in obtaining quality IOS imaging results. Our aim was to simplify the choice of post processing techniques, by comparing a variety of those previously performed. To reach our goal, we have designed and constructed our own IOS imaging system, including hardware and software. We carried out preliminary tests on real mice to improve our understanding of the IOS imaging modality and the signal components involved. We then created a mathematical model of the mouse brains' IOS response and analysed the performance of a variety of signal processing techniques, including those typically applied to IOS imaging. Next, we compared these techniques on real imaging data. These include: averaging over trials, spatial Gaussian filtering, temporal low pass filtering, temporal band pass filtering, global signal regression, principal component analysis, truncated differences. We were particularly focused on comparing the effectiveness of each technique’s ability to remove noise and extract the IOS signal for both spatial and temporal responses, both quantitatively and qualitatively. We performed careful analysis of the techniques and the advantages and disadvantages are presented such that the best choice can be made for a given IOS imaging setup. Our results concluded that Gaussian filtering is the most effective choice for improving the spatial IOS response with minimal complexity. For temporal data, low pass filtering and band pass filtering provided a significant improvement over averaging with reasonable complexity, however if periodic stimuli is not possible, GSR or truncated difference should be considered as these techniques also significantly improve the signal and do not require a periodic stimuli. Other PCA variations can be considered but require careful consideration of the component selection technique to be used and are highly dependent on the quality of the raw data.
Naderian, Azadeh. "Retinal optical imaging of intrinsic signals." Thèse, 2017. http://hdl.handle.net/1866/20273.
Повний текст джерелаAkhlagh, Moayed Alireza. "In vivo Imaging of Light Induced Intrinsic Optical Signals in the Chicken Retina with a Combined Ultra-High Resolution Optical Coherence Tomography and Electroretinography System." Thesis, 2012. http://hdl.handle.net/10012/7208.
Повний текст джерелаRinguette, Dene. "Application of Vertical-cavity Surface-emitting Lasers for Simultaneous Laser Speckle Contrast and Intrinsic Optical Signal Imaging: Toward Chronic Portable Cortical Hemodynamic Imaging." Thesis, 2012. http://hdl.handle.net/1807/32620.
Повний текст джерелаGuy, Julien. "Order under the guise of chaos: functional neuroanatomy of the somatosensory "barrel" cortex of the reeler mutant mouse." Doctoral thesis, 2015. http://hdl.handle.net/11858/00-1735-0000-0028-8752-9.
Повний текст джерелаRanjbar-Salmloo, Yadollah. "Sensory coding in supragranular cells of the vibrissal cortex in anesthetized and awake mice." Phd thesis, 2017. http://hdl.handle.net/1885/147598.
Повний текст джерелаStodieck, Sophia Katharina. "The role of postsynaptic density (PSD) proteins PSD-95 and PSD-93 for mouse visual cortical plasticity and vision." Doctoral thesis, 2016. http://hdl.handle.net/11858/00-1735-0000-0023-3F15-A.
Повний текст джерелаShankar, Mohan. "Sampling and Signal Estimation in Computational Optical Sensors." Diss., 2007. http://hdl.handle.net/10161/445.
Повний текст джерелаAksoylar, Aydan. "Modeling and model-aware signal processing methods for enhancement of optical systems." Thesis, 2016. https://hdl.handle.net/2144/19504.
Повний текст джерелаMathevula, Langutani Eulenda. "Optical and magnetic properties of rare earth Doped α-Fe2O3 for future bio-imaging applications". Thesis, 2018. http://hdl.handle.net/10500/26881.
Повний текст джерелаPhysics
Nattar, Ranganath Gayathri. "Signal propagation in recurrent networks of mouse barrel cortex." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-12-4577.
Повний текст джерелаtext
Truong, Van Tri. "Optical imaging and two-photon microscopy study of hemodynamic changes contralateral to ictal focus during epileptiform discharges." Thèse, 2015. http://hdl.handle.net/1866/12441.
Повний текст джерелаIt has been well demonstrated that focal seizures are associated with a significant increase in regional cerebral blood flow to actively supply discharging neurons with oxygenated hemoglobin. There is also some evidence to suggest that focal seizures elicit early hemodynamic changes in the contralateral homotopic area, although this has been less well documented. In this study, we aim to better characterize the nature of early hemodynamic responses contralateral to the epileptic focus during seizures. We used intrinsic optical imaging (IOI) and two-photon laser microscopy to measure the hemodynamic changes in the homotopic contralateral area following focal seizures induced by an injection of 4-aminopyridine (4-AP) in the mouse somatosensory neocortex. In the study using IOI, oxyhemoglobin (HbO), deoxyhemoglobin (HbR) and cerebral blood flow (CBF) changes were observed in the homotopic area contralateral to the focus during all seizures. However, these changes were rather heterogenous, lacking any consistent or reproducible pattern. Our two-photon study showed no significant hemodynamic changes at the capillary level in the homotopic area contralateral to the ictal focus during epileptic spike trains. However, these findings must be interpreted cautiously in light of several limitations we encountered during the experiments. Specifically, we were unable to simultaneously record electrophysiology in the contralateral homotopic area. Furthermore, during our two-photon experiments, we failed to induce long ictal discharges (inducing only spike trains) had a limited sampling of the contralateral homotopic area and reduced power as a result of low mice survival rate. We conclude by providing alternatives to possibly improve future experiments.
Castonguay, Alexandre. "Modulation de l'activité de structures cérébrales sous-corticales par optogénétique." Thèse, 2013. http://hdl.handle.net/1866/10247.
Повний текст джерелаOptogentics is a promising technic for neuronal activity modulation. By inserting a microbial opsin in the plasma membrane and by its photonic activation, it is possible to regulate neuronal activity with high temporal and spatial resolution. A lot of work has been done to characterize and synthetize new opsins. Thus, a wide variety of opsins are now available, presenting different kinetics and sensibility to specific wavelengths. Indeed, different opsins can either increase or decrease neuronal activity such as channelrhodopsin-2 (ChR2) or halorhodopsin (NpHR), respectively. This technology has the potential to stimulate a specific region within the brain in a highly reversible manner. However, little work was accomplished in this way, because to limitations due to absorption and scattering of light in biological tissue. This master’s thesis presents the conception of a side-firing optical fiber, capable of guiding light to specific structures within the brain. We conducted in vivo experiments in the visual system of transgenic mice expressing ChR2 in the entire central nervous system. In the visual system, retinal inputs are relayed to the lateral geniculate nucleus (LGN) before reaching the primary visual cortex (V1). To validate the capacity of the designed optogenetic assembly to stimulate specific sub-populations of neurons, we took advantage of the retinotopic organization existing in the visual system. By optogenetically stimulating the LGN and rotating the optical fiber around its axis with a motor, it is possible to sequentially stimulate different portions of this thalamic structure and consequently, different portions of the visual field. Activation of thalamic projections will be recorded in area V1 using intrinsic optical imaging, a technic allowing to image variations of blood oxygenation and blood volume in neuronal tissue over large cortical areas. Activation at the level of the cortex will reveal the spatial extent of the optogenetic stimulation in the LGN as retinotopic organization is maintained in V1 cortical area. In vivo experiments showed that displacing the optical fiber in the LGN allowed stimulation of different neuronal populations within this thalamic structure. In conclusion, this study demonstrates our capacity to develop a fiber-based system capable of optogenetically stimulating neuronal tissue with high spatial precision.
Mané, Maria. "Spektrale Eigenschaften des intrinsischen optischen Signals während hypoxieinduzierter Spreading Depression im Hippokampus der Ratte." Doctoral thesis, 2011. http://hdl.handle.net/11858/00-1735-0000-0006-B204-0.
Повний текст джерелаVanni, Matthieu P. "Les cartes fonctionnelles dans le cortex visuel du chat : nouvelles stratégies d’évaluation en imagerie optique et mise en évidence de l’organisation anatomo-fonctionnelle." Thèse, 2010. http://hdl.handle.net/1866/4105.
Повний текст джерелаThe clustering of neurons of similar properties is at the basis of the brain modular architecture and is considered as a strategy to optimized processing. One consequence of this clustering is the presence of functional maps in the primary visual cortex of several mammals based on features such as orientation, direction of motion and stimulus position (retinotopy). The first section of this thesis was aimed at characterizing the modular organization of functions in primary and higher-order areas. First, we investigated the possibility that a fundamental cell property, the receptive field center / surround suppression, could be orderly represented in the primary visual cortex. Second, we determined the level of modular organization in area 21a for two key properties, orientation and direction of motion. All studies were based on the optical imaging of intrinsic signals in anesthetized cats. Results indicate the presence of high and low surround suppression modules in the primary visual cortex (areas 17 and 18). To date, such organization has been discovered only in a higher-order area in primate. A modular organization for orientation, similar to the one observed in areas 17 and 18 was observed in area 21a. On the other hand, in contrast to area 18, no direction modules were discovered in area 21a. Overall, the first part of this thesis increased our knowledge about the anatomo-fonctional organization of cat visual cortex. They will also be instrumental to better understand the factors leading to the presence of a modular organization in the cortex. The second section of this thesis was directed to the development of a novel quantitative tool for the temporal analysis of optical imaging intrinsic signals. This new approach, based on Fourier decomposition, allowed to greatly increase the signal to noise ratio of the recordings. Until now, this analysis was only been based on single harmonic quantification, limiting its application for orientation and rétinotopy mapping only. A model exploiting higher harmonics was then developed to estimate additional parameters such as the receptive field size and direction selectivity. Thereafter, this model was validated with success by conventional approaches on the primary visual cortex.
Haller, Mirjam. "Structure and function of KATP-channels in inspiratory neurons of mice." Doctoral thesis, 2000. http://hdl.handle.net/11858/00-1735-0000-0006-B5A4-C.
Повний текст джерела