The Moon Illusion Explained Introduction and Summary
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12 Retina Gabriele K
299 12 Retina Gabriele K. Lang and Gerhard K. Lang 12.1 Basic Knowledge The retina is the innermost of three successive layers of the globe. It comprises two parts: ❖ A photoreceptive part (pars optica retinae), comprising the first nine of the 10 layers listed below. ❖ A nonreceptive part (pars caeca retinae) forming the epithelium of the cil- iary body and iris. The pars optica retinae merges with the pars ceca retinae at the ora serrata. Embryology: The retina develops from a diverticulum of the forebrain (proen- cephalon). Optic vesicles develop which then invaginate to form a double- walled bowl, the optic cup. The outer wall becomes the pigment epithelium, and the inner wall later differentiates into the nine layers of the retina. The retina remains linked to the forebrain throughout life through a structure known as the retinohypothalamic tract. Thickness of the retina (Fig. 12.1) Layers of the retina: Moving inward along the path of incident light, the individual layers of the retina are as follows (Fig. 12.2): 1. Inner limiting membrane (glial cell fibers separating the retina from the vitreous body). 2. Layer of optic nerve fibers (axons of the third neuron). 3. Layer of ganglion cells (cell nuclei of the multipolar ganglion cells of the third neuron; “data acquisition system”). 4. Inner plexiform layer (synapses between the axons of the second neuron and dendrites of the third neuron). 5. Inner nuclear layer (cell nuclei of the bipolar nerve cells of the second neuron, horizontal cells, and amacrine cells). 6. Outer plexiform layer (synapses between the axons of the first neuron and dendrites of the second neuron). -
Pupil Responses Associated with Coloured Afterimages Are Mediated by the Magno-Cellular Pathway
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Aston Publications Explorer Vision Research 43 (2003) 1423–1432 www.elsevier.com/locate/visres Pupil responses associated with coloured afterimages are mediated by the magno-cellular pathway S. Tsujimura *, J.S. Wolffsohn, B. Gilmartin Neurosciences Research Institute, Aston University, Aston Triangle, Birmingham B4 7ET, UK Received 14 August 2002; received in revised form 27 January 2003 Abstract Sustained fixation of a bright coloured stimulus will, on extinction of the stimulus and continued steady fixation, induce an afterimage whose colour is complementary to that of the initial stimulus; an effect thought to be caused by fatigue of cones and/or of cone-opponent processes to different colours. However, to date, very little is known about the specific pathway that causes the coloured afterimage. Using isoluminant coloured stimuli recent studies have shown that pupil constriction is induced by onset and offset of the stimulus, the latter being attributed specifically to the subsequent emergence of the coloured afterimage. The aim of the study was to investigate how the offset pupillary constriction is generated in terms of input signals from discrete functional elements of the magno- and/or parvo-cellular pathways, which are known principally to convey, respectively, luminance and colour signals. Changes in pupil size were monitored continuously by digital analysis of an infra-red image of the pupil while observers viewed isoluminant green pulsed, ramped or luminance masked stimuli presented on a computer monitor. It was found that the amplitude of the offset pupillary constriction decreases when a pulsed stimulus is replaced by a temporally ramped stimulus and is eliminated by a luminance mask. -
Localisation of Visual Hallucinations
BRITISH MEDICAL JOURNAL 16 JULY 1977 147 of hypothermia; the duration of cardiac arrest; and the disturbances of sleep or consciousness.4 Hallucinations may be promptness and correctness of treatment. Peterson's pessi- evoked by sensory deprivation, but other factors are usually mistic report from California,8 in which all 15 near-drowned present; thus the "black-patch" delirium that may follow children who had fits, fixed dilated pupils, flaccidity, and loss cataract extraction in the elderly probably results from sensory Br Med J: first published as 10.1136/bmj.2.6080.147 on 16 July 1977. Downloaded from of pain sensation suffered severe anoxic encephalopathy, deprivation and mild senile brain changes and is more frequent may be explained by the high water temperatures there. In when hearing is also impaired.5 warm water the protective effect of hypothermia against brain Hallucinations may be due to focal lesions. Past experiences, damage would be missing. In contrast was the case described the quality of eidetic imagery, and psychodynamic "actors in Trondheim, Norway,9 in which a 5-year-old fell through influence the content of organic hallucinosis,6 and it would be ice in fresh water with an outside temperature of 10° below unwise to lean too heavily on the occurrence and nature of zero centigrade. He was in the water for 22 minutes and was hallucinosis in localising intracranial lesions. Visual hallucina- brought out apparently dead, with widely dilated pupils and tions are a relatively infrequent accompaniment oflesions ofthe bluish white skin. He was warmed up (the method was not calcarine cortex (Brodmann's area 17), which has few thalamo- described) and-despite the risks noted above-was given cortical connections; yet they may occur as a false-localising external cardiac massage without suffering ventricular symptom of frontal or subtentorial lesions. -
Real Time Measurement and Processing of Pupillary Light Reflex for Early Detection of Disease
Journal of Computers Real Time Measurement and Processing of Pupillary Light Reflex for Early Detection of Disease Ippei Torii*, Takahito Niwa Aichi Institute of Technology, Dept. of Information Science, 1247 Yachigusa, Yakusa-cho, Toyota, Aichi, Japan. * Corresponding author. Tel.: 81-565-48-8121; email: mac[aitech.ac.jp Manuscript submitted January 10, 2019; accepted March 8, 2019. doi: 10.17706/jcp.14.3.161-169 Abstract: Recently, pupillary measurements have begun to be considered effective in the diagnosis of various physical conditions. Apart from optic neuropathy and retinal disorders, which are ocular diseases, diversions can be expected in the diagnosis of autonomic disturbance due to sympathetic and parasympathetic nerve disorders, cranial nerve disorders, cerebral infarction, depression, and diabetes. In this study, we have developed a real-time pupil diameter measuring system that is inexpensive and does not require a complicated device. When strong light is projected onto the eyeball, this system can measure the reaction time until the start of miosis, the time to achieve maximal miosis, and the difference in reaction speed of the left and right eyes. With this system, the status of a disease can be judged based on the distance from the threshold value. Key words: Real time measurement, eye movement, early detection of disease, image processing. 1. Introduction There are approximately one hundred million photoreceptor cells in the retina of human eyes. Light that shines on those cells is converted to nerve signals, which transmit the information to the brain, resulting in the visual recognition of objects. When light is radiated onto the eye, the pupillary light reflex is triggered, causing the pupillary diameter to decrease with a time delay of less than 1 sec. -
Subliminal Afterimages Via Ocular Delayed Luminescence: Transsaccade Stability of the Visual Perception and Color Illusion
ACTIVITAS NERVOSA SUPERIOR Activitas Nervosa Superior 2012, 54, No. 1-2 REVIEW ARTICLE SUBLIMINAL AFTERIMAGES VIA OCULAR DELAYED LUMINESCENCE: TRANSSACCADE STABILITY OF THE VISUAL PERCEPTION AND COLOR ILLUSION István Bókkon1,2 & Ram L.P. Vimal2 1Doctoral School of Pharmaceutical and Pharmacological Sciences, Semmelweis University, Budapest, Hungary 2Vision Research Institute, Lowell, MA, USA Abstract Here, we suggest the existence and possible roles of evanescent nonconscious afterimages in visual saccades and color illusions during normal vision. These suggested functions of subliminal afterimages are based on our previous papers (i) (Bókkon, Vimal et al. 2011, J. Photochem. Photobiol. B) related to visible light induced ocular delayed bioluminescence as a possible origin of negative afterimage and (ii) Wang, Bókkon et al. (Brain Res. 2011)’s experiments that proved the existence of spontaneous and visible light induced delayed ultraweak photon emission from in vitro freshly isolated rat’s whole eye, lens, vitreous humor and retina. We also argue about the existence of rich detailed, subliminal visual short-term memory across saccades in early retinotopic areas. We conclude that if we want to understand the complex visual processes, mere electrical processes are hardly enough for explanations; for that we have to consider the natural photobiophysical processes as elaborated in this article. Key words: Saccades Nonconscious afterimages Ocular delayed bioluminescence Color illusion 1. INTRODUCTION Previously, we presented a common photobiophysical basis for various visual related phenomena such as discrete retinal noise, retinal phosphenes, as well as negative afterimages. These new concepts have been supported by experiments (Wang, Bókkon et al., 2011). They performed the first experimental proof of spontaneous ultraweak biophoton emission and visible light induced delayed ultraweak photon emission from in vitro freshly isolated rat’s whole eye, lens, vitreous humor, and retina. -
The Moon Illusion and Size–Distance Scaling—Evidence for Shared Neural Patterns
The Moon Illusion and Size–Distance Scaling—Evidence for Shared Neural Patterns Ralph Weidner1*, Thorsten Plewan1,2*, Qi Chen1, Axel Buchner3, Peter H. Weiss1,4, and Gereon R. Fink1,4 Abstract ■ A moon near to the horizon is perceived larger than a moon pathway areas including the lingual and fusiform gyri. The func- at the zenith, although—obviously—the moon does not change tional role of these areas was further explored in a second ex- its size. In this study, the neural mechanisms underlying the periment. Left V3v was found to be involved in integrating “moon illusion” were investigated using a virtual 3-D environ- retinal size and distance information, thus indicating that the ment and fMRI. Illusory perception of an increased moon size brain regions that dynamically integrate retinal size and distance was associated with increased neural activity in ventral visual play a key role in generating the moon illusion. ■ INTRODUCTION psia; Sperandio, Kaderali, Chouinard, Frey, & Goodale, Although the moon does not change its size, the moon 2013; Enright, 1989; Roscoe, 1989). near to the horizon is perceived as relatively larger com- One concept of size constancy scaling implies that the pared with when it is located at the zenith. This phenome- retinal image size and the estimated distance of an object non is called the “moon illusion” and is one of the oldest are conjointly considered, thereby enabling constant size visual illusions known (Ross & Plug, 2002). Despite exten- perception of objects at different distances (Kaufman & sive research, no consensus has been reached regarding Kaufman, 2000). With respect to the moon illusion, appar- the underlying perceptual and neural correlates (Ross & ent distance theories, for example, propose that “the per- Plug, 2002; Hershenson, 1989). -
Visual Perception in Migraine: a Narrative Review
vision Review Visual Perception in Migraine: A Narrative Review Nouchine Hadjikhani 1,2,* and Maurice Vincent 3 1 Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA 2 Gillberg Neuropsychiatry Centre, Sahlgrenska Academy, University of Gothenburg, 41119 Gothenburg, Sweden 3 Eli Lilly and Company, Indianapolis, IN 46285, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-617-724-5625 Abstract: Migraine, the most frequent neurological ailment, affects visual processing during and between attacks. Most visual disturbances associated with migraine can be explained by increased neural hyperexcitability, as suggested by clinical, physiological and neuroimaging evidence. Here, we review how simple (e.g., patterns, color) visual functions can be affected in patients with migraine, describe the different complex manifestations of the so-called Alice in Wonderland Syndrome, and discuss how visual stimuli can trigger migraine attacks. We also reinforce the importance of a thorough, proactive examination of visual function in people with migraine. Keywords: migraine aura; vision; Alice in Wonderland Syndrome 1. Introduction Vision consumes a substantial portion of brain processing in humans. Migraine, the most frequent neurological ailment, affects vision more than any other cerebral function, both during and between attacks. Visual experiences in patients with migraine vary vastly in nature, extent and intensity, suggesting that migraine affects the central nervous system (CNS) anatomically and functionally in many different ways, thereby disrupting Citation: Hadjikhani, N.; Vincent, M. several components of visual processing. Migraine visual symptoms are simple (positive or Visual Perception in Migraine: A Narrative Review. Vision 2021, 5, 20. negative), or complex, which involve larger and more elaborate vision disturbances, such https://doi.org/10.3390/vision5020020 as the perception of fortification spectra and other illusions [1]. -
Care of the Patient with Accommodative and Vergence Dysfunction
OPTOMETRIC CLINICAL PRACTICE GUIDELINE Care of the Patient with Accommodative and Vergence Dysfunction OPTOMETRY: THE PRIMARY EYE CARE PROFESSION Doctors of optometry are independent primary health care providers who examine, diagnose, treat, and manage diseases and disorders of the visual system, the eye, and associated structures as well as diagnose related systemic conditions. Optometrists provide more than two-thirds of the primary eye care services in the United States. They are more widely distributed geographically than other eye care providers and are readily accessible for the delivery of eye and vision care services. There are approximately 36,000 full-time-equivalent doctors of optometry currently in practice in the United States. Optometrists practice in more than 6,500 communities across the United States, serving as the sole primary eye care providers in more than 3,500 communities. The mission of the profession of optometry is to fulfill the vision and eye care needs of the public through clinical care, research, and education, all of which enhance the quality of life. OPTOMETRIC CLINICAL PRACTICE GUIDELINE CARE OF THE PATIENT WITH ACCOMMODATIVE AND VERGENCE DYSFUNCTION Reference Guide for Clinicians Prepared by the American Optometric Association Consensus Panel on Care of the Patient with Accommodative and Vergence Dysfunction: Jeffrey S. Cooper, M.S., O.D., Principal Author Carole R. Burns, O.D. Susan A. Cotter, O.D. Kent M. Daum, O.D., Ph.D. John R. Griffin, M.S., O.D. Mitchell M. Scheiman, O.D. Revised by: Jeffrey S. Cooper, M.S., O.D. December 2010 Reviewed by the AOA Clinical Guidelines Coordinating Committee: David A. -
Handbook of EEG INTERPRETATION This Page Intentionally Left Blank Handbook of EEG INTERPRETATION
Handbook of EEG INTERPRETATION This page intentionally left blank Handbook of EEG INTERPRETATION William O. Tatum, IV, DO Section Chief, Department of Neurology, Tampa General Hospital Clinical Professor, Department of Neurology, University of South Florida Tampa, Florida Aatif M. Husain, MD Associate Professor, Department of Medicine (Neurology), Duke University Medical Center Director, Neurodiagnostic Center, Veterans Affairs Medical Center Durham, North Carolina Selim R. Benbadis, MD Director, Comprehensive Epilepsy Program, Tampa General Hospital Professor, Departments of Neurology and Neurosurgery, University of South Florida Tampa, Florida Peter W. Kaplan, MB, FRCP Director, Epilepsy and EEG, Johns Hopkins Bayview Medical Center Professor, Department of Neurology, Johns Hopkins University School of Medicine Baltimore, Maryland Acquisitions Editor: R. Craig Percy Developmental Editor: Richard Johnson Cover Designer: Steve Pisano Indexer: Joann Woy Compositor: Patricia Wallenburg Printer: Victor Graphics Visit our website at www.demosmedpub.com © 2008 Demos Medical Publishing, LLC. All rights reserved. This book is pro- tected by copyright. No part of it may be reproduced, stored in a retrieval sys- tem, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Library of Congress Cataloging-in-Publication Data Handbook of EEG interpretation / William O. Tatum IV ... [et al.]. p. ; cm. Includes bibliographical references and index. ISBN-13: 978-1-933864-11-2 (pbk. : alk. paper) ISBN-10: 1-933864-11-7 (pbk. : alk. paper) 1. Electroencephalography—Handbooks, manuals, etc. I. Tatum, William O. [DNLM: 1. Electroencephalography—methods—Handbooks. WL 39 H23657 2007] RC386.6.E43H36 2007 616.8'047547—dc22 2007022376 Medicine is an ever-changing science undergoing continual development. -
The Effect of Eye Movements and Blinks on Afterimage Appearance and Duration
Journal of Vision (2015) 15(3):20, 1–15 http://www.journalofvision.org/content/15/3/20 1 The effect of eye movements and blinks on afterimage appearance and duration School of Psychology, Cardiff University, # Georgina Powell Cardiff, Wales, UK $ School of Psychology, Cardiff University, # Petroc Sumner Cardiff, Wales, UK $ Lyon Neuroscience Research Center, # Aline Bompas Centre Hospitalier Vinatier, Bron, Cedex, France $ The question of whether eye movements influence argued that afterimage signals are inherently ambigu- afterimage perception has been asked since the 18th ous, and this could explain why their visibility is century, and yet there is surprisingly little consensus on influenced by cues, such as surrounding luminance how robust these effects are and why they occur. The edges, more than are real stimuli (Powell, Bompas, & number of historical theories aiming to explain the Sumner, 2012). Helmholtz (1962) identified another cue effects are more numerous than clear experimental that is important to take into account when conducting demonstrations of such effects. We provide a clearer afterimage experiments: characterization of when eye movements and blinks do or do not affect afterimages with the aim to distinguish For obtaining really beautiful positive after- between historical theories and integrate them with a images, the following additional rules should be modern understanding of perception. We found neither saccades nor pursuit reduced strong afterimage observed. Both before and after they are devel- duration, and blinks actually increased afterimage oped, any movement of the eye or any sudden duration when tested in the light. However, for weak movement of the body must be carefully avoided, afterimages, we found saccades reduced duration, and because under such circumstances they invariably blinks and pursuit eye movements did not. -
The Simplest Method to Measure the Geocentric Lunar Distance: a Case of Citizen Science
The simplest method to measure the geocentric lunar distance: a case of citizen science Jorge I. Zuluaga1,a, Juan C. Figueroa2,b and Ignacio Ferrin1,c 1 FACom - Instituto de Física - FCEN, Universidad de Antioquia, Calle 70 No. 52-21, Medellín, Colombia 2 Independent Software Developer ABSTRACT We present the results of measuring the geocentric lunar distance using what we propose is the simplest method to achieve a precise result. Although lunar distance has been systematically measured to a precision of few millimeters using powerful lasers and retroreflectors installed on the moon by the Apollo missions, the method devised and applied here can be readily used by nonscientist citizens (e.g. amateur astronomers or students) and it requires only a good digital camera. After launching a citizen science project called the “Aristarchus Campaign”, intended to involve astronomy enthusiasts in scientific measurement of the Lunar Eclipse of 15 April 2014, we compiled and measured a series of pictures obtained by one of us (J.C. Figueroa). These measurements allowed us to estimate the lunar distance to a precision of ~3%. We describe here how to perform the measurements and the method to calculate from them the geocentric lunar distance using only the pictures time stamps and a precise measurement of the instantaneous lunar apparent diameter. Our aim here is not to provide any improved measurement of a well- known astronomical quantity, but rather to demonstrate how the public could be engaged in scientific endeavors and how using simple instrumentation and readily available technological devices such as smartphones and digital cameras, any person can measure the local Universe as ancient astronomers did. -
Localizing and Lateralizing Value of Epileptic Symptoms in Temporal Lobe Epilepsy
Localizing and Lateralizing Value of Epileptic Symptoms in Temporal Lobe Epilepsy Jean-Marc Saint-Hilaire and Mary Anne Lee ABSTRACT: The symptoms and signs associated with all stages of a temporal lobe seizure may be helpful in determining both the localization and lateralization of seizure onset. Auras, when present, may be very suggestive of temporal lobe onset and may further localize to a mesiobasal or lateral temporal lobe site of onset. During the ictus, automatisms and motor phenomena may be highly indicative of temporal lobe seizure activity and may even help lateralize the discharge. In the post-ictal period, motor paresis and aphasia are helpful in lateralization. Video E.E.G. data has provided extensive information on the utility of ictal symptomatology in seizure localization. Thus, the seizure semiology provides important adjunctive information in evaluating patients for epilepsy surgery and should be concordant with information obtained from ictal EEG, neuroimaging and neuropsychology. RÉSUMÉ: La valeur des symptômes épileptiques pour la localisation et la latéralisation dans l'épilepsie temporale. Les symptômes et les signes associés à tous les stades d'une crise temporale peuvent aider à déterminer la localisation et la latéralisation du site de déclenchement de la crise. L'aura, quand elle est présente, peut être très suggestive d'un début temporal et peut localiser de façon plus précise le site de déclenchement de la crise. Pendant la crise, les automatismes et les phénomènes moteurs peuvent être hautement indicateurs d'une activité ictale temporale et peuvent même aider à latéraliser la décharge. Dans la période post-ictale, la parésie motrice et l'aphasie peuvent aider à la latéralisation.