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Photoreceptor Cells: Specialized cells that detect and transduce light. They are classified into two types based on their light reception structure, the ciliary photoreceptors and the rhabdomeric photoreceptors with Microvilli. Ciliary photoreceptor cells use Opsins that activate a Phosphodiesterase phosphodiesterase cascade. Rhabdomeric photoreceptor cells use opsins that activate a Phospholipase c cascade.

The Retina

JoVE 10857

The retina is a layer of nervous tissue at the back of the eye that transduces light into neural signals. This process, called phototransduction, is carried out by rod and cone photoreceptor cells in the back of the retina.

Photoreceptors have outer segments with stacks of membranous disks that contain photopigment molecules—such as rhodopsin in rods. The photopigments absorb light, triggering a cascade of molecular events that results in the cell becoming hyperpolarized (with a more negative membrane potential) relative to when it is in the dark. This hyperpolarization decreases neurotransmitter release. Thus, unlike stimuli for most other sensory neurons, light induces a reduction in neurotransmitter release from photoreceptors. Although rods and cones both detect light, they play distinct roles in vision. Rods are highly sensitive to light, and therefore predominate in low-light conditions, such as at night. Cones are less sensitive and are used for most daytime vision. Cones are densely concentrated in the fovea—a small depression near the center of the retina that contains very few rods—and provide a high level of visual acuity in the area where the eye is focused. Cones also convey color information, because the different types—S (short), M (medium), and L (long) in humans—maximally absorb different wa

 Core: Sensory Systems

Vision

JoVE 10858

Vision is the result of light being detected and transduced into neural signals by the retina of the eye. This information is then further analyzed and interpreted by the brain. First, light enters the front of the eye and is focused by the cornea and lens onto the retina—a thin sheet of neural tissue lining the back of the eye. Because of refraction through the convex lens of the eye, images are projected onto the retina upside-down and reversed. Light is absorbed by the rod and cone photoreceptor cells at the back of the retina, causing a decrease in their rate of neurotransmitter release. In addition to detecting photons of light, color information is also encoded here, since different types of cones respond maximally to different wavelengths of light. The photoreceptors then send visual information to bipolar cells near the middle of the retina, which is followed by projection to ganglion cells at the front of the retina. Horizontal and amacrine cells mediate lateral interactions between these cell types, integrating information from multiple photoreceptors. This integration aids in the initial processing of visual information, such as detecting simple features, like edges. Along with glial cells, the axons of the retinal ganglion cells make up the optic nerve, which transmits visual information to the brain. The optic nerve partially cro

 Core: Sensory Systems

Ophthalmoscopic Examination

JoVE 10146

Source: Richard Glickman-Simon, MD, Assistant Professor, Department of Public Health and Community Medicine, Tufts University School of Medicine, MA


The simplest ophthalmoscopes consist of an aperture to look through, a diopter indicator, and a disc for selecting lenses. The ophthalmoscope is primarily used to examine the fundus, or the…

 Physical Examinations II

Color Afterimages

JoVE 10194

Source: Laboratory of Jonathan Flombaum—Johns Hopkins University


Human color vision is impressive. People with normal color vision can tell apart millions of individual hues. Most amazingly, this ability is achieved with fairly simple hardware.


Part of the power of human color vision comes from a…

 Sensation and Perception

Isolation of Primary Murine Retinal Ganglion Cells (RGCs) by Flow Cytometry

1Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, 2Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, 3Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, 4Department of Pharmaceutical Sciences, University of Tennessee Health Science Center

JoVE 55785

 Bioengineering

Limbal Approach-Subretinal Injection of Viral Vectors for Gene Therapy in Mice Retinal Pigment Epithelium

1Department of Biomedical Sciences, Seoul National University College of Medicine, 2FARB Laboratory, Biomedical Research Institute, Seoul National University Hospital, 3College of Life Sciences, Gwangju Institute of Science and Technology, 4Department of Ophthalmology, Seoul National University College of Medicine

JoVE 53030

 Neuroscience

Large-Scale Purification of Porcine or Bovine Photoreceptor Outer Segments for Phagocytosis Assays on Retinal Pigment Epithelial Cells

1INSERM, U968, 2Sorbonne Universités, UPMC Paris 06, UMR_S 968, Institut de la Vision, 3CNRS, UMR_7210, 4Department of Biological Sciences, Center for Cancer, Genetic Diseases and Gene Regulation, Fordham University

JoVE 52100

 Immunology and Infection

Vibratome Sectioning Mouse Retina to Prepare Photoreceptor Cultures

1Department of Genetics, UMR_S 968, Institut de la Vision, 2Department of Visual Information, UMR_S 968, Institut de la Vision, 3Exploratory Team, UMR_S 968, Institut de la Vision, 4Sorbonne Universités, Paris 06, UMR_S 968, Institut de la Vision, 5INSERM, U968, Institut de la Vision, 6CNRS, UMR_7210, Institut de la Vision

JoVE 51954

 Neuroscience

In vivo Imaging of Optic Nerve Fiber Integrity by Contrast-Enhanced MRI in Mice

1Hans Berger Department of Neurology, Jena University Hospital, 2Immunology, Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, 3Institute of Diagnostic and Interventional Radiology, Medical Physics Group, Jena University Hospital

JoVE 51274

 Neuroscience

Subretinal Injection of Gene Therapy Vectors and Stem Cells in the Perinatal Mouse Eye

1Bernard and Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University, 2Institute of Human Nutrition, College of Physicians & Surgeons, Columbia University, 3Omics Laboratory, University of Iowa, 4Department of Ophthalmology and Visual Sciences, University of Iowa

JoVE 4286

 Medicine
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