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Optic Nerve: The 2nd cranial nerve. The optic nerve conveys visual information from the retina to the brain. The nerve carries the axons of the retinal ganglion cells which sort at the optic chiasm and continue via the optic tracts to the brain. The largest projection is to the lateral geniculate nuclei; other important targets include the superior colliculi and the suprachiasmatic nuclei. Though known as the second cranial nerve, it is considered part of the central nervous system.
 JoVE 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

 Science Education: Essentials of Physical Examinations III

Cranial Nerves Exam I (I-VI)

JoVE Science Education

Source: Tracey A. Milligan, MD; Tamara B. Kaplan, MD; Neurology, Brigham and Women's/Massachusetts General Hospital, Boston, Massachusetts, USA

During each section of the neurological testing the examiner uses the powers of observation to assess the patient. In some cases cranial nerve dysfunction is readily apparent: a patient might mention a characteristic chief complaint (such as loss of smell or diplopia), or a visually evident physical sign of cranial nerve involvement, such as in facial nerve palsy. However, in many cases a patient's history doesn't directly suggest cranial nerve pathologies, as some of them (such as sixth nerve palsy) may have subtle manifestations and can only be uncovered by a careful neurological exam. Importantly, a variety of pathological conditions that are associated with alterations in mental status (such as some neurodegenerative disorders or brain lesions) can also cause cranial nerve dysfunction, therefore any abnormal findings during a mental status exam should prompt a careful and complete neurological exam. The cranial nerve examination is applied neuroanatomy. The cranial nerves are symmetrical, therefore while performing the examination each side should be compared to the other. A physician should approach the examination in a systematic fashion an

 JoVE Medicine

Experimental Glaucoma Induced by Ocular Injection of Magnetic Microspheres

1Ocular Biology and Therapeutics, University College London Institute of Ophthalmology, 2University College London Institue of Ophthalmology, 3Moorfields Eye Hospital, 4NIHR Biomedical Research Centre, Moorfields Eye Hospital, 5Schepens Eye Research Institute, Harvard Medical School, 6Hoffman-La Roche


JoVE 52400

 Science Education: Essentials of Physical Examinations II

Ophthalmoscopic Examination

JoVE Science Education

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 inner wall of the posterior eye, which consists of the choroid, retina, fovea, macula, optic disc, and retinal vessels (Figure 1). The spherical eyeball collects and focuses light on the neurosensory cells of the retina. Light is refracted as it passes sequentially through the cornea, the lens, and the vitreous body. The first landmark observed during the funduscopic exam is the optic disc, which is where the optic nerve and retinal vessels enter the back of the eye (Figure 2). The disc usually contains a central whitish physiologic cup where the vessels enter; it normally occupies less than half the diameter of the entire disc. Just lateral and slightly inferior is the fovea, a darkened circular area that demarcates the point of central vision. Around this is the macula. A blind spot approximately 15° temporal to the line of gaze results from a lack of photoreceptor cells at the optic disc.

 Science Education: Essentials of Physical Examinations II

Eye Exam

JoVE Science Education

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

Proper evaluation of the eyes in a general practice setting involves vision testing, orbit inspection, and ophthalmoscopic examination. Before beginning the exam, it is crucial to be familiar with the anatomy and physiology of the eye. The upper eyelid should be slightly over the iris, but it shouldn't cover the pupil when open; the lower lid lies below the iris. The sclera normally appears white or slightly buff in color. The appearance of conjunctiva, a transparent membrane covering the anterior sclera and the inner eyelids, is a sensitive indicator of ocular disorders, such as infections and inflammation. The tear-producing lacrimal gland lies above and lateral to the eyeball. Tears spread down and across the eye to drain medially into two lacrimal puncta before passing into the lacrimal sac and nasolacrimal duct to the nose. The iris divides the anterior from the posterior chamber. Muscles of the iris control the size of the pupil, and muscles of the ciliary body behind it control the focal length of the lens. The ciliary body also produces aqueous humor, which largely determines intraocular pressure (Figure 1). Cranial nerve

 Science Education: Essentials of Sensation and Perception

Finding Your Blind Spot and Perceptual Filling-in

JoVE Science Education

Source: Laboratory of Jonathan Flombaum—Johns Hopkins University

In the back of everyone's eye is a small piece of neural tissue called the retina. The retina has photosensitive cells that respond to stimulation by light. The responses of these cells are sent into the brain through the optic nerve, a bundle of neural fibers. In each retina there is a place somewhere in the periphery where the outputs from retinal cells collect and the bundled optic nerve exits to the brain. At that location, there is no photosensitivity-whatever light reflects from the world and lands in that position does not produce a signal in the brain. As a result, humans have a blind spot, a place in the visual field for which they don't process incoming stimuli. However, people are not aware that they have blind spots; there is not an empty hole in the visual images in front of the eyes. So what do people see in their blind spots? The brain actually fills-in missing input based on the surroundings. This video demonstrates how to find a person's blind spot, and how to investigate the mechanisms of perceptual filling-in.

 JoVE Biology

Implementation of a Coherent Anti-Stokes Raman Scattering (CARS) System on a Ti:Sapphire and OPO Laser Based Standard Laser Scanning Microscope

1INSERM U1051, Institut des Neurosciences de Montpellier (INM), Université de Montpellier, 2Université de Nîmes, 3CNRS, IES, UMR 5214, 4Aix-Marseille Université, CNRS, École Centrale Marseille, Institut Fresnel, UMR 7249, 5Montpellier RIO Imaging (MRI)


JoVE 54262

 JoVE Medicine

Use of Rabbit Eyes in Pharmacokinetic Studies of Intraocular Drugs

1Department of Ophthalmology, Seoul National University Bundang Hospital, 2Department of Ophthalmology, College of Medicine, Seoul National University, 3Department of Ophthalmology, Hanyang University Hospital, 4Department of Ophthalmology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, 5Department of Clinical Pharmacology, Seoul National University Hospital, 6Department of Clinical Pharmacology, Seoul National University Bundang Hospital


JoVE 53878

 JoVE Biology

Method for the Assessment of Effects of a Range of Wavelengths and Intensities of Red/near-infrared Light Therapy on Oxidative Stress In Vitro

1Experimental and Regenerative Neurosciences, School of Animal Biology, The University of Western Australia, 2School of Animal Biology and The Oceans Institute, The University of Western Australia, 3Experimental and Regenerative Neurosciences, School of Anatomy, Physiology and Human Biology, The University of Western Australia


JoVE 52221

 JoVE Neuroscience

Imaging Ca2+ Dynamics in Cone Photoreceptor Axon Terminals of the Mouse Retina

1Institute for Ophthalmic Research, University of Tübingen, 2Graduate School of Cellular & Molecular Neuroscience, University of Tübingen, 3Bernstein Centre for Computational Neuroscience, University of Tübingen, 4Molecular Genetics Laboratory, University of Tübingen, 5Centre for Ophthalmology, University of Tübingen


JoVE 52588

 JoVE Neuroscience

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

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