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Retinal signal processing

Rami Burstein, Rodrigo Noseda, Anne B Fulton
BACKGROUND: Photophobia is commonly associated with migraine, meningitis, concussion, and a variety of ocular diseases. Advances in our ability to trace multiple brain pathways through which light information is processed have paved the way to a better understanding of the neurobiology of photophobia and the complexity of the symptoms triggered by light. PURPOSE: The purpose of this review is to summarize recent anatomical and physiological studies on the neurobiology of photophobia with emphasis on migraine...
March 2019: Journal of Neuro-ophthalmology: the Official Journal of the North American Neuro-Ophthalmology Society
William J Harrison, Reuben Rideaux
The extent to which visual inference is shaped by attentional goals is unclear. Voluntary attention may simply modulate the priority with which information is accessed by the higher cognitive functions involved in perceptual decision making. Alternatively, voluntary attention may influence fundamental visual processes, such as those involved in segmenting an incoming retinal signal into a structured scene of coherent objects, thereby determining perceptual organization. Here we tested whether the segmentation and integration of visual form can be determined by an observer's goals, by exploiting a novel variant of the classical Kanizsa figure...
February 13, 2019: Attention, Perception & Psychophysics
Renata Lejkowska, Miłosz Piotr Kawa, Ewa Pius-Sadowska, Dorota Rogińska, Karolina Łuczkowska, Bogusław Machaliński, Anna Machalińska
This study aimed to investigate whether the transplantation of genetically engineered bone marrow-derived mesenchymal stromal cells (MSCs) to overexpress brain-derived neurotrophic factor (BDNF) could rescue the chronic degenerative process of slow retinal degeneration in the rd6 (retinal degeneration 6) mouse model and sought to identify the potential underlying mechanisms. Rd6 mice were subjected to the intravitreal injection of lentivirally modified MSC-BDNF or unmodified MSC or saline. In vivo morphology, electrophysiological retinal function (ERG), and the expression of apoptosis-related genes, as well as BDNF and its receptor (TrkB), were assessed in retinas collected at 28 days and three months after transplantation...
February 12, 2019: International Journal of Molecular Sciences
T Tony Yang, Minh Nguyet Thi Tran, Weng Man Chong, Chia-En Huang, Jung-Chi Liao
Primary cilia play a vital role in cellular sensing and signaling. An essential component of ciliogenesis is intraflagellar transport (IFT) involving in IFT-protein recruitment, axonemal engagement of IFT-protein complexes, etc. The mechanistic understanding of these processes at the ciliary base was largely missing, because it is challenging to observe the motion of IFT proteins in this crowded region using conventional microscopy. Here, we report short trajectory tracking of IFT proteins at the base of mammalian primary cilia by optimizing single-particle tracking photoactivated localization microscopy (sptPALM) for IFT88-mEOS4b in live human retinal pigment epithelial cells...
February 13, 2019: Molecular Biology of the Cell
Elaine M Morazzani, Jaimee R Compton, Dagmar H Leary, Angela V Berry, Xin Hu, Juan Marugan, Pamela J Glass, Patricia M Legler
The alphaviral nonstructural protein 2 (nsP2) cysteine proteases (EC 3.4.22.-) are essential for the proteolytic processing of the nonstructural (ns) polyprotein and are validated drug targets. A common secondary role of these proteases is to antagonize the effects of interferon (IFN). After delineating the cleavage site motif of the Venezuelan equine encephalitis virus (VEEV) nsP2 cysteine protease, we searched the human genome to identify host protein substrates. Here we identify a new host substrate of the VEEV nsP2 protease, human TRIM14, a component of the mitochondrial antiviral-signaling protein (MAVS) signalosome...
February 8, 2019: Antiviral Research
Ze Zhang, Wen-Ying Liu, Yu-Pu Diao, Wei Xu, Yu-Heng Zhong, Jia-Yi Zhang, Michael Lazarus, Yuan-Yuan Liu, Wei-Min Qu, Zhi-Li Huang
Sleep is regulated by homeostatic process and circadian clock. Light indirectly modulates sleep by entraining the circadian clock to the solar day. Light can also influence sleep independent of photo-entrainment [1]. An acute light exposure could induce sleep, and an acute dark pulse could increase wakefulness in nocturnal animals [1, 2]. The photoreceptors and cell types in the retina that mediate light and dark effects on sleep are well characterized [1-4]. A few studies have explored the brain region involved in acute light induction of sleep...
January 15, 2019: Current Biology: CB
Jia Jia Lek, Bao N Nguyen, Allison M McKendrick, Algis J Vingrys
Purpose: Aging and glaucoma both result in contrast processing deficits. However, it is unclear the extent to which these functional deficits arise from retinal or post-retinal neuronal changes. This study aims to disentangle the effects of healthy human aging and glaucoma on retinal and post-retinal contrast processing using visual electrophysiology. Methods: Steady-state pattern electroretinograms (PERG) and pattern visual evoked potentials (PVEP) were simultaneously recorded across a range of contrasts (0%, 4%, 9%, 18%, 39%, 73%, 97%; 0...
January 2, 2019: Investigative Ophthalmology & Visual Science
Shaohua Pi, Acner Camino, Xiang Wei, Tristan T Hormel, William Cepurna, John C Morrison, Yali Jia
Phase wrapping is a crucial issue in Doppler optical coherence tomography (OCT) and restricts its automatic implementation for clinical applications that quantify total retinal blood flow. We propose an automated phase-unwrapping technique that takes advantage of the parabolic profile of blood flow velocity in vessels. Instead of inspecting the phase shift manually, the algorithm calculates the gradient magnitude of the phase shift on the cross-sectional image and automatically detects the presence of phase wrapping...
January 2019: Journal of Biomedical Optics
Jihyun Yeonan-Kim, Gregory Francis
Visual persistence (stimulus perception that prolongs for a few milliseconds after the physical disappearance of the stimulus) and afterimages (an illusory percept that lingers after the physical disappearance of the stimulus at the retinotopic location of the preceding stimulus) are classic perceptual phenomena reflecting temporal characteristics of the visual system. These phenomena are modulated by some common stimulus aspects: A longer stimulus generates shorter persistence and a longer afterimage and a lower spatial-frequency stimulus generates shorter persistence and a stronger afterimage...
January 28, 2019: Psychological Review
Shaker A Mousa, Bassam M Ayoub
Repositioning of dipeptidyl peptidase-4 inhibitors and glucagon like peptide-1 receptor agonists is a breakthrough in the field of neural regeneration research increasing glucagon like peptide-1 bioavailability, hence its neuroprotective activities. In this article, the authors suggest not only crossing blood-brain barrier and neurodegenerative disease as off target for dipeptidyl peptidase-4 inhibitors and glucagon like peptide-1 receptor agonists, but also for ophthalmic preparations for diabetic retinopathy, which may be the latest breakthrough in the field if prepared and used in an appropriate nano-formulation to target the retinal nerves...
May 2019: Neural Regeneration Research
Lung-Chi Lee, Ke-Hao Huang, Yi-Hao Chen, Hsin-Ting Lin, Chia-Chen Hsu, Ming-Cheng Tai, Chang-Min Liang, Jiann-Torng Chen, Ching-Long Chen
RATIONALE: Optical coherence tomography angiography (OCT-A) has the advantage to visualize the microvascular structure of the retina in vivo and was utilized clinically in various neovascular retinal diseases. The OCT-A has also been used to examine the lesion in multifocal choroiditis and panuveitis (MCP). This study aimed to describe a case of MCP and present the disease process of a punched-out lesion in the chorioretina with neovascular activity using OCT-A. PATIENTS CONCERNS: A 32-year-old female Caucasian patient presented with a 2-week history of progressive blurred vision in her right eye with photophobia and a diminished temporal visual field...
January 2019: Medicine (Baltimore)
Jeffrey R Millman, Teresa Doggett, Christina Thebeau, Sheng Zhang, Clay F Semenkovich, Rithwick Rajagopal
High acuity vision is a heavily energy-consuming process, and the retina has developed several unique adaptations to precisely meet such demands while maintaining transparency of the visual axis. Perturbations to this delicate balance cause blinding illnesses, such as diabetic retinopathy. Therefore, the understanding of energy metabolism changes in the retina during disease is imperative to the development of rational therapies for various causes of vison loss. The recent advent of commercially-available extracellular flux analyzers has made the study of retinal energy metabolism more accessible...
January 7, 2019: Journal of Visualized Experiments: JoVE
Xiaorui Li, Jing Liu, Josephine Hoh, Ju Liu
Müller cells are the major glial cells spanning the entire layer of the retina and maintaining retinal structure. Under pathological conditions, Müller cells are involved in retinal angiogenesis, a process of growing new blood vessels from pre-existing capillaries. In response to hypoxia, high glucose, and inflammation conditions, multiple signaling pathways are activated in Müller cells, followed by the increased production of proangiogenic factors including vascular endothelial growth factor, basic fibroblast growth factor, matrix metalloproteinases, Netrin-4, and angiopoietin-like 4...
December 27, 2018: Translational Research: the Journal of Laboratory and Clinical Medicine
Ta-Ching Chen, Pin-Yi She, Dong Feng Chen, Jui-Hsien Lu, Chang-Hao Yang, Ding-Siang Huang, Pao-Yang Chen, Chen-Yu Lu, Kin-Sang Cho, Hsin-Fu Chen, Wei-Fang Su
Optic neuropathy is one of the leading causes of irreversible blindness caused by retinal ganglion cell (RGC) degeneration. The development of induced pluripotent stem cell (iPSC)-based therapy opens a therapeutic window for RGC degeneration, and tissue engineering may further promote the efficiency of differentiation process of iPSCs. The present study was designed to evaluate the effects of a novel biomimetic polybenzyl glutamate (PBG) scaffold on culturing iPSC-derived RGC progenitors. The iPSC-derived neural spheres cultured on PBG scaffold increased the differentiated retinal neurons and promoted the neurite outgrowth in the RGC progenitor layer...
January 5, 2019: International Journal of Molecular Sciences
Bertan Cakir, Michael Reich, Stefan Lang, Anima Bühler, Christoph Ehlken, Bastian Grundel, Milena Stech, Sabine Reichl, Andreas Stahl, Daniel Böhringer, Hansjürgen Agostini, Clemens Lange
INTRODUCTION: To quantify optical coherence tomography angiography (OCTA) signal changes at the level of the choriocapillaris (CC) in patients with different stages of central serous chorioretinopathy (CSC) and to explore any correlation between subretinal fluid (SRF) and retinal pigment epithelium (RPE) alterations and the OCTA CC signal. METHODS: One hundred one CSC eyes and 42 healthy control eyes were included in this retrospective study. CSC patients were allocated into four groups: acute, non-resolving, chronic atrophic and inactive CSC...
January 7, 2019: Ophthalmology and Therapy
Ian F Harrison, Rozalind Whitaker, Pietro Maria Bertelli, James M O'Callaghan, Lajos Csincsik, Martina Bocchetta, Da Ma, Alice Fisher, Zeshan Ahmed, Tracey K Murray, Michael J O'Neill, Jonathan D Rohrer, Mark F Lythgoe, Imre Lengyel
Visual impairments, such as difficulties in reading and finding objects, perceiving depth and structure from motion, and impaired stereopsis, have been reported in tauopathy disorders, such as frontotemporal dementia (FTD). These impairments however have been previously attributed to cortical pathologies rather than changes in the neurosensory retina or the optic nerve. Here, we examined tau pathology in the neurosensory retina of the rTg(tauP301L)4510 mouse model of FTD. Optic nerve pathology in mice was also assessed using MRI, and corresponding measurements taken in a cohort of five FTD sufferers and five healthy controls...
January 7, 2019: Acta Neuropathologica Communications
Evgenii Boriushkin, Hui Zhang, Mitchell Becker, Janet Peachey, Mohammad A Shatat, Ralf H Adams, Anne Hamik
Angiogenesis is a multistep process that requires highly regulated endothelial cell (EC) behavior. The transcription factor Krüppel-like factor 4 (KLF4) is a critical regulator of several basic EC functions; we have recently shown that KLF4 disturbs pathological (tumor) angiogenesis by mediating the expression of members of VEGF and Notch signaling pathways. Notch signaling is central to orchestration of sprouting angiogenesis but little is known about the upstream regulation of Notch itself. To determine the role of KLF4 in normal (developmental) angiogenesis, we used a mouse retinal angiogenesis model...
January 3, 2019: Angiogenesis
Marion F Haug, Manuela Berger, Matthias Gesemann, Stephan C F Neuhauss
The retina is a complex neural circuit, which processes and transmits visual information from light perceiving photoreceptors to projecting retinal ganglion cells. Much of the computational power of the retina rests on signal integrating interneurons, such as bipolar cells. Commercially available antibodies against bovine and human conventional protein kinase C (PKC) α and -β are frequently used as markers for retinal ON-bipolar cells in different species, despite the fact that it is not known which bipolar cell subtype(s) they actually label...
January 2, 2019: Histochemistry and Cell Biology
O S Kozhevnikova, A Zh Fursova, A M Markovets, D V Telegina, N A Muraleva, N G Kolosova
Age-related macular degeneration (AMD) is the leading cause of vision loss among the elderly. By clinical signs, there are two forms of AMD: the atrophic or dry (~ 90% of all cases) and wet or neovascular AMD (~10% of cases). Anti-vascular endothelial growth factor (VEGF) intravitreal agents are the only successful treatment for wet AMD. However, there are emerging signals that anti-VEGF treatment can potentially increase development of atrophic AMD. There is neither a treatment of the dry AMD due poor understanding of the pathogenesis and retina aging process in general...
2018: Advances in Gerontology, Uspekhi Gerontologii
Hunter Porter, Hui Qi, Nicole Prabhu, Richard Grambergs, Joel McRae, Blake Hopiavuori, Nawajes Mandal
Sphingosine 1-phosphate (S1P) signaling regulates numerous biological processes including neurogenesis, inflammation and neovascularization. However, little is known about the role of S1P signaling in the eye. In this study, we characterize two sphingosine kinases (SPHK1 and SPHK2), which phosphorylate sphingosine to S1P, and three S1P receptors (S1PR1, S1PR2 and S1PR3) in mouse and rat eyes. We evaluated sphingosine kinase and S1P receptor gene expression at the mRNA level in various rat tissues and rat retinas exposed to light-damage, whole mouse eyes, specific eye structures, and in developing retinas...
December 5, 2018: International Journal of Molecular Sciences
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