Dissertations / Theses on the topic 'Visual photoreceptors'
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Hart, Nathan Scott. "Avian photoreceptors." Thesis, University of Bristol, 1998. http://hdl.handle.net/1983/f35814d2-b726-4d74-b05d-6fb30c89f894.
Full textBaverstock, Jenny. "Biochemistry of visual transduction in squid photoreceptors." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302983.
Full textIgnatova, I. (Irina). "Processing of visual information by microvillar photoreceptors." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526221526.
Full textBurton, B. G. "Visual ecology, biophysics and the adaptability of fly photoreceptors." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597151.
Full textWolfram, Verena. "Impact of light history on processing of visual signals in Drosophila photoreceptors." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615093.
Full textLampic, Marusa. "Restoration of visual function by transplantation of optogenetically engineered photoreceptors." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS233.
Full textA major challenge in treatment of retinal degenerative diseases with transplantation of replacement photoreceptors is the difficulty in inducing the grafted cells to grow and maintain light-sensitive outer segments in the host retina, which depends on proper interaction with the underlying retinal pigment epithelium (RPE). For an RPE-independent treatment approach, we introduced a hyperpolarizing microbial opsin into photoreceptor precursors from newborn mice, and transplanted them into blind mice lacking the photoreceptor layer. These optogenetically transformed photoreceptors were light responsive and their transplantation lead to the recovery of visual function, as shown by ganglion cell recordings and behavioral tests. Subsequently, we generated cone photoreceptors from human induced pluripotent stem cells (hiPSCs), expressing the chloride pump Jaws. After transplantation into blind mice, we observed light-driven responses at the photoreceptor and ganglion cell level. These results demonstrate that structural and functional retinal repair is possible by combining stem cell therapy and optogenetics
Whiteley, Simon J. O. "Deterioration and repair of visual function in the Royal College of Surgeons rat." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.344049.
Full textMosk, Virginia Jan. "The visual system of seahorses and pipefish : a study of visual pigments and other characteristics." University of Western Australia. School of Animal Biology, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0081.
Full textLessios, Nicolas. "Using electroretinograms and multi-model inference to identify spectral classes of photoreceptors and relative opsin expression levels." PEERJ INC, 2017. http://hdl.handle.net/10150/625519.
Full textLü, Bin. "An investigation into the functional activity within the subcortical visual centers and retinae of the Royal College of Surgeons rat using C-fos immunohistochemistry." Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310774.
Full textDonahue, Vicki S. "Phospholipase c activity in retinal pigment epithelium." Virtual Press, 1997. http://liblink.bsu.edu/uhtbin/catkey/1041916.
Full textDepartment of Biology
Heimonen, K. (Kyösti). "Processing of visual information in dim light:functional variability, matched filtering and spike coding in cockroach (Periplaneta americana) photoreceptors." Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514289491.
Full textGomes, André Marcelo Vieira. "Estudo do buraco macular fechado cirurgicamente: avaliação da relação entre a integridade da camada de fotorreceptores e a acuidade visual final por meio da tomografia de coerência óptica." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/5/5149/tde-11122007-112047/.
Full textPurpose: To evaluate the integrity of the retina photoreceptor layer as determined by optical coherence tomography and its relationship with final visual outcome in successfully closed idiopathic macular holes. Methods: Successfully operated patients with a minimal follow-up of 12 months, underwent complete ophthalmic exam involving post-operative best corrected visual acuity using logMar scale, macula biomicroscopy and indirect ophthalmoscopy and fluorescein angiography. Complete epidemiologic data was collected as well as time duration, pre-op visual acuity, and size and Gass classification of the holes. Optical coherence tomography images of the layer corresponding to the transition between inner and outer segments of the photoreceptors were meticulously generated using commercially available Stratus OCT (OCT3). Qualitative analysis of this layer was carried out, in a masked fashion, by a certified and well experienced examiner. Based on increasing integrity showed in the images, patients were then distributed in 3 groups: 1, 2 and 3. Group 1 integrity from 1 to 33%, group 2 from 34 to 66%, and group 3 from 67 to 100%. Results: A total of 39 eyes of 37 patients were included in the study. Among all patients, 12 were included in group 1, 7 in group 3 and 20 in group 3. There were 22 female (59,5%) and 15 male (40,5%). Mean age was 68.2 years varying from 51 to 83 years of age. Mean post-op follow-up time was 38.5 months. When comparing groups 1 and 3, best corrected final visual acuity improved in both groups but dramatically in group 3 (better integrity) (p<0.001). Pre-operative size and time duration of the hole did not correlate with better visual acuity (p=0.223 and p=0.559 respectively). Mean pre-op visual acuity was better in group 3 than in group 1 (p=0.012). Conclusion: Data obtained in our study indicate that there is a strong correlation between better integrity of the photoreceptor layer, as determined by optical coherence tomography, and a more successful final, long term, visual acuity in patients with idiopathic macular hole successfully operated. Although final visual acuity has improved in all groups, there was statistical difference between groups 1 and 3. Pre-operative size and time duration of the hole did not have impact on final visual acuity. Better pre-op visual acuity may have an effect on final outcome.
Yang, Xuchun. "Probing the Photochemistry of Rhodopsin Through Population Dynamics Simulations." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1563553836632515.
Full textGozem, Samer. "Understanding the Relationship Between Thermal and Photochemical Isomerization in Visual Receptors." Bowling Green State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1371498160.
Full textAlarcón, Martínez Luis. "Estudios electrorretinográficos en modelos de neurodegeneración en el sistema visual del roedor adulto." Doctoral thesis, Universidad de Murcia, 2009. http://hdl.handle.net/10803/11000.
Full textNeurodegenerative diseases are characterized by degeneration and death of neurons which are unable to recover after a given insult, thus impairing functional recuperation. Because of this, there is no cure for diseases such as Alzheimer, Parkinson or Glaucoma. The retina is a projection of the central nervous system (CNS) located in the eye and therefore, isolated from the rest of the CNS. This makes the retina a very good model for experimental manipulation. In this work we have studied the functional changes in the retina by full field electroretinograme (ERG). This technique records the electric response of the retina after presentation of homogeneous light stimuli. We have studied the effects that optic nerve sections, increase of the intraocular pressure and phototoxicity have on ERG recordings. These lesions impair selectively certain retinal neuronal populations and imitate neurodegenerative diseases as Glaucoma or Age-related Macular Degeneration.
Bonezzi, Paul J. "The development of outer retinal photoresponsivity and the effects of sensory deprivation." University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1602525875711526.
Full textGoh, Debbie. "Assessing visual function following transplantation of mouse ESC-derived rod photoreceptor precursors." Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/1574309/.
Full textGontang, Allison Camille. "Identification and characterization of regulators of photoreceptor targeting in drosophila visual system /." May be available electronically:, 2009. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Full textField, Gregory Darin. "The limits to absolute visual sensitivity /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/10552.
Full textRubin, Glen R. "Comparisons between behavioral and electrophysiological measures of visual function in rodent models of retinal degeneration." Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2009. https://www.mhsl.uab.edu/dt/2009p/rubin.pdf.
Full textDunn, Felice Audris. "Gain control of rod and cone vision in the mammalian retina /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/10642.
Full textSothilingam, Vithiyanjali [Verfasser], and Alfred [Akademischer Betreuer] Nordheim. "Dissection of visual signalling based on functionally specific rod photoreceptor mutants / Vithiyanjali Sothilingam ; Betreuer: Alfred Nordheim." Tübingen : Universitätsbibliothek Tübingen, 2016. http://d-nb.info/1164168908/34.
Full textBittencourt, Guido Barbieri. "Morfologia dos fotorreceptores e genética dos pigmentos visuais de Bothrops jararaca e Crotalus durissus terrificus (Serpentes, Viperidae)." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/47/47132/tde-24012019-150846/.
Full textSerpents inhabit a great diversity of habitats around the planet. Such environmental variability implies the performance of distinct ecological niches and behavior patterns that are related to different visual system adaptations. The diversity of environments inhabited by snakes and their evolutionary history provides a privileged investigative opportunity on the adaptive organization of the visual systems, specific behaviors and phylogeny. The comparative analysis of the retina of those animals provide many information concerning behavior and ecological adaptations related to their respective environment and circadian rhythm patterns. In this study, we performed genetic analysis of the opsin genes and morphological analysis of the photoreceptors of two snakes from the Viperidae family, Bothrops jararaca and Crotalus durissus terrificus. Three subjects of each species were collected at the Butantan Institute. Total RNA was extracted from homogenized retinas, and mRNA was converted to cDNA by reverse transcriptase reaction. The opsin genes lws, rh1 and sws1 were amplified by polymerase chain reactions (PCR), using specific primers. Each opsin is expressed in a different photoreceptor population and is maximally responsive to a determined spectral absorption peak (max) that was inferred according to the protein structure. Additionally, photorreceptor cell populations were analyzed using immunohistochemistry technique. Results point out to the same morphological cell populations and the same absorption peak in their respective opsins in the two species: double and single cones with the LWS photopigment and estimated max at ~555nm; single cones with the SWS1 photopigment and max at ~360nm; and rods with the rhodopsin RH1 photopigment and max at ~500nm. In this way, great similarity of ecological niche and natural history was concluded for both species, which present adaptations to the nocturnal habit. This should demonstrate the great evolutionary success and versatility attained by the rod-domminated duplex retina. In B. jararaca and C. d. terrificus, snakes from the Crotalinae subfamily, those retinal features are summed to the capability of infra-red detection, which point out to similarity with snakes from the basal Henophidia group
Van, Epps Heather Alane. "Insights from the characterization and cloning of the zebrafish visual mutant, nrc : synaptojanin's essential role in photoreceptor ribbon synaptic function /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/9205.
Full textTaylor, Michael Robert. "Genetic and biochemical analysis of zebrafish with visual function defects /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/9242.
Full textMorimoto, Mai. "Signal transformation at the input and output of the Drosophila visual system." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267911.
Full textAmador, Viviani Mantovani. "Estudo genético dos pigmentos visuais em primatas do Novo Mundo." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/47/47135/tde-04042016-124725/.
Full textColor vision in vertebrates requires the presence of at least two different classes of cones in the retina, and a neural substrate capable to compare the activation of the different photoreceptors, which ultimately leads to color perception. Old World Monkeys (OWM), including humans, have trichromatic color vision, whereas New World Monkeys (NWM) have visual pigment genes polymorphism and among primates, are the only group with dichromatic or trichromatic individuals in the same species. This polymorphism in NWM occurs due to the variability of genes that express the opsins responsible for absorbing medium or long wavelengths. The genetic studies of color vision are fundamental for the comprehension of color perception in these animals and it could help to understand the color vision evolution in Primates. The aim of this work is to characterize the visual pigment diversity (LWS/MWS and SWS1) in NWM species by genetic analysis and estimate the opsin spectral absorption peak, based on the amino acid sequence. Blood, feces and hair were collected from six primate genres from different regions of Brazil (Pará, Rio de Janeiro, Rio Grande do Norte and São Paulo): Cebus apella, Callithrix jacchus, Alouatta clamitans, Alouatta caraya, Lagothrix lagothricha, Ateles belzebuth and Brachyteles arachnoides. The amino acid sequences found in important positions of the SWS1 gene (52, 86, 93, 114 and 118) were different among some species. In C. apella, L. lagotricha, A. belzebuth and B. arachnoides was found the amino acid sequence LLPAT. In C. jacchus, A. caraya and A. clamitans the amino acid sequence was LLPGT. It was observed in previous studies that residue 50 of the SWS1 gene in the New World primates is important to determining the spectral absorption peak of the visual pigments expressed by this gene. The LWS and MWS genes of C. jacchus have been studied and the amino acids located at positions 180, 277 and 285 have been identified. Five different combinations were found among the individuals analyzed: SFT, SYA, SYT, AYA and AYT. Two alleles, AYA and SYA, were described for the first time in this species. The present study filled some gaps in the literature and brought new information on the genetic diversity of visual pigments in New World primates
Guo, Peiyi. "A Glia-Mediated Feedback Mechanism for the Termination of Drosophila Visual Response: A Dissertation." eScholarship@UMMS, 2009. http://escholarship.umassmed.edu/gsbs_diss/499.
Full textNi, Lina. "Maintenance of Visual Sensitivity in the Drosophila Eye: A Dissertation." eScholarship@UMMS, 2010. https://escholarship.umassmed.edu/gsbs_diss/457.
Full textGuo, Peiyi. "A Glia-Mediated Feedback Mechanism for the Termination of Drosophila Visual Response: A Dissertation." eScholarship@UMMS, 2010. https://escholarship.umassmed.edu/gsbs_diss/499.
Full textVladislav, Džinić. "Morfološke karakteristike makule kao prognostički faktor poboljšanja vidne oštrine u terapiji pacijenata obolelih od dijabetesnog makularnog edema." Phd thesis, Univerzitet u Novom Sadu, Medicinski fakultet u Novom Sadu, 2016. http://www.cris.uns.ac.rs/record.jsf?recordId=101090&source=NDLTD&language=en.
Full textThe aim of this study was to investigate the influence of the central macular thickness (CMT) and the presence of sub retinal fluid on visual acuity (VA) in patients with diabetic macular edema, as well as the impact of preservation and continuity of the photoreceptor inner/outer segment junction (IS / OS - complex ) and external limiting membrane (ELM) as a prognostic factor in improving visual acuity after the applied therapy in patients with diabetic macular edema (DME). Materials and Methods: this retrospective - prospective randomized clinical study included 100 patients who were divided into two groups. Group A - a prospective part of the study, consisted of 50 patients (50 eyes), with the diagnosis of diabetic macular edema in which laser photocoagulation and / or anti-VEGF therapy (bevacizumab) was indicated. Group B - retrospective group, consisted of 50 patients (58 eyes), who were previously treated for diabetic macular edema either with laser photocoagulation and / or anti-VEGF therapy (bevacizumab). After complete ophthalmologic examination, which consisted of the determination of visual acuity (measured with Snellen charts), biomicroscopy, intraocular pressure measurement and inspection of the fundus, optical coherence tomography was performed in all patients (using the Stratus® OCT, Carl Zeiss Meditec and Copercnicus® Optopol). Analysis of OCT image, included the determination of the central macular thickness (CMT), presence of sub retinal fluid, as well as an assessment of the preservation of the continuity of the photoreceptor inner/outer segment junction (IS/OS - complex) and external limiting membrane (ELM). CMT is calculated using software of the OCT apparatus and expressed as the mean value for all 9 ETDRS fields. Presence of sub retinal fluid is classified as positive if it is identified in at least one cross-section of OCT tomogram. Preserved continuity of IS / OS complex and ELM is analyzed in each individual OCT cross-section image and divided into 3 categories. First - if it is preserved in all cross sections images, the second - if it is preserved only in certain sections and the third - if the IS / OS complex and ELM were not able to identify in OCT tomograms. The results indicate that the presence of sub retinal fluid before the applied therapy has no statistically significant effect on improving visual acuity after the applied therapy in patients of group A (pA = 0.915), and statistical significance was not also confirmed in any of the patients who were previously treated by DME - Group B (pB = 0.772). Mean CMT and VA values of patients in group A was 474μm ± 140,67μm and 0.25 ± 0.20. After receiving therapy mean visual acuity was 0.41 ± 0.25, while the value of the mean CMT was 343.68μm± 99.03μm. Significant improvement in visual acuity was achieved after the treatment in group A (pVA = 0.0001) together with statistically significant reduction in central macular thickness (pCMT = 0.0001). Correlation of VA with the values of CMT before applied therapy shows statistically significant negative correlation (r = -0.391; p = 0.005), while after the applied therapy statistical significance was not observed (r = -0.047; p = 0.746). Analyzing the values of CMT before the applied therapy with the values of VA after the treatment statistically significant negative correlation was observed, higher values of CMT before the applied therapy restrict visual acuity improvement after the applied therapy (r = -0.393; p = 0.005). Analyzing OCT tomograms in the patients in group A, before the applied therapy, fully preserved continuity of IS/OS complex and ELM in all the sections was found in 23 and 27 of the eyes, in certain sections in 18 and 16 of the eyes, and could not be identified in 9 and 7 eyes. Statistically significant improvement in VA, after the applied therapy, in patients in group A is observed, depending on the preservation of continuity of IS/OS complex (F = 5.550, p = 0.007) and ELM (F = 5.428, p = 0.008). Univariate and multivariate analysis with cut off VA value of 0.1 and step improvements of 0.1 points to statistically significant predictor of IS/OS complex (p = 0.012 and p = 0.032) and ELM (p = 0.003 and p = 0.018) in improving the VA after the applied therapy. Patients with preserved continuity of IS/OS complex in all sections are 9.5 times (OR = 9.500) more likely to improve the VA after receiving therapy compared to patients where continuity of IS/OS complex is not noticeable. Patients with preserved continuity of IS/OS complex in the some sections are 7 times more likely (OR = 7.000) for the improvement of visual acuity after treatment compared to those in which the IS/OS is not detectable. Patients with preserved continuity of ELM in all sections are 34.5 times (OR = 34,500) a greater chance to improve visual acuity compared to patients where ELM is not apparent. Patients with preserved continuity of ELM in the some sections are 18 times more likely (OR = 18,000) to improve the VA after treatment compared to those in which the ELM is not apparent. In addition to statistically significant impact of preservation of continuity of IS/OS complex and ELM for VA improvement after the treatment, statistically significant positive correlation between visual acuity before and after treatment (r = 0.869; p = 0.0001) was observed. In Group B patients, the mean CMT and VA value was 253,72μm±75,268μm and 0.68 ± 0.29. There is a statistically significant difference in the VA values compared to the preservation of continuity of IS/OS complex (F = 107.913, p = 0.0001) and ELM (F = 25.619, p = 0.0001). Comparing the values of parameters for both groups, statistically significant difference in CMT values and mean VA was observed. CMT values were lower (t = 5.355, p = 0.0001) while VA values were higher (t = 5.137, p = 0.0001), in group B. The analysis of preservation of continuity of IS/OS complex (χ2 = 0.119, p = 0.730) and ELM (χ2 = 2.957, p = 0.085) did not show a statistically significant difference. Conclusion: The relationship of visual acuity with central macular thickness shows the different levels of visual acuity for the same value of the central macular thickness. A significant impact on VA in patients with DME has maintained integrity of the external limiting membrane (ELM) and the photoreceptors inner/outer segments junction (IS/OS complex) evaluated on the basis of OCT - tomograms. Preservation of the integrity of the ELM and IS/OS complex in all sections of the OCT tomogram before applied therapy in patients with DME can be considered a positive prognostic factor in improving visual acuity after receiving therapy. In patients with preserved continuity of ELM and IS/OS complex in all sections before applied therapy the CMT value has no effect on the improvement of visual function after treatment. Regardless of the type of applied therapy, anti-VEGF and/or laser photocoagulation preserved integrity of IS/OS complex and ELM has a positive correlation with visual acuity. The presence of sub retinal fluid does not affect the visual acuity in patients with DME. The values of VA before treatment influence the improvement of visual acuity after treatment.
Falkowski, Marcin. "The spectral and temporal properties of fiddler crab photoreceptors in the context of predator avoidance." Phd thesis, 2017. http://hdl.handle.net/1885/144592.
Full textSmolka, Jochen. "Sampling Visual Space: Topography, colour vision and visually guided predator avoidance in fiddler crabs (Uca vomeris)." Phd thesis, 2009. http://hdl.handle.net/1885/7107.
Full textResearch School of Biological Sciences (RSBS, now RSB), and the Australian National University for providing funding through an ANU PhD scholarship; the Australian Department of Education, Employment and Workplace Relations for an International Postgraduate Research Scholarship; the German National Academic Foundation and the Zeiss Foundation for support through a Heinz-Dürr Scholarship; and the Australian Institute of Marine Sciences for providing accommodation and facilities during fieldwork in Queensland.
Sabbah, Shai. "Functional diversity in colour vision of fish." Thesis, 2012. http://hdl.handle.net/1974/7199.
Full textThesis (Ph.D, Biology) -- Queen's University, 2012-05-14 13:16:50.276
(8803004), Logan C. Ganzen. "Drug Screening Utilizing the Visual Motor Response of a Zebrafish Model of Retinitis Pigmentosa." Thesis, 2020.
Find full text"Puzzling Connections between Behavior, Spectral Photoreceptor Classes and Visual System Simplification: Branchiopod Crustaceans and Unconventional Color Vision." Doctoral diss., 2016. http://hdl.handle.net/2286/R.I.40271.
Full textDissertation/Thesis
Doctoral Dissertation Biology 2016