DOCSLIB.ORG

Binocular Suppression in the Macaque Lateral Geniculate Nucleus Reveals Early Competitive Interactions Between the Eyes

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Binocular Suppression in the Macaque Lateral Geniculate Nucleus Reveals Early Competitive Interactions Between the Eyes Research Article: New Research | Sensory and Motor Systems Binocular suppression in the macaque lateral geniculate nucleus reveals early competitive interactions between the eyes https://doi.org/10.1523/ENEURO.0364-20.2020 Cite as: eNeuro 2021; 10.1523/ENEURO.0364-20.2020 Received: 20 August 2020 Revised: 6 November 2020 Accepted: 28 November 2020 This Early Release article has been peer-reviewed and accepted, but has not been through the composition and copyediting processes. The final version may differ slightly in style or formatting and will contain links to any extended data. Alerts: Sign up at www.eneuro.org/alerts to receive customized email alerts when the fully formatted version of this article is published. Copyright © 2021 Dougherty et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed. 1 Binocular suppression in the macaque lateral geniculate nucleus 2 reveals early competitive interactions between the eyes 3 4 Abbreviated title: Binocular modulation in primate LGN 5 6 7 Kacie Dougherty1,2, Brock M. Carlson1, Michele A. Cox1,3, Jacob A. Westerberg1, Wolf Zinke1, Michael 8 C. Schmid4, Paul R. Martin5, Alexander Maier1 9 10 1Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for 11 Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37235, USA 12 2Princeton Neuroscience Institute, Princeton University, Princeton, NJ 09540, USA 13 3Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY 14620, USA 14 4Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5 CH-1700 Fribourg, 15 Switzerland 16 5Save Sight Institute and Australian Research Council Centre of Excellence for Integrative Brain 17 Function, The University of Sydney, Sydney, New South Wales 2006, Australia. 18 19 KD, MAC, MCS, AM Designed Research; KD, BMC, JAW, WZ Performed research; PRM Contributed 20 unpublished analytic tools; KD, WZ, PRM Analyzed data; KD, AM Wrote the paper 21 22 Correspondence to Kacie Dougherty, PhD. Email: [email protected] 23 24 6 Figures, 0 Tables, 0 Multimedia 25 Abstract: 245 words, Significance Statement: 104 words, Introduction: 750 words, Discussion: 1549 26 words 27 28 Funding: Supported by a research grant from the National Eye Institute (1R01EY027402-03) and 29 National Eye Institute Training Grant (5T32EY007135-23) to JAW and K.D, National Institute of Mental 30 Health Training Grant (5T32MH065214-17) to K.D, and National Eye Institute Training Grant 31 (1F31EY031293-22) to J.A.W. M.C.S. is supported by ERC grant OptoVision 637638. 32 Conflicts of Interest: The authors report no conflicts of interest. 33 34 Acknowledgments: We thank M. Schall, B. Mitchell, L. Daumail, M. Feurtado, C. Jones, K. Shuster, M. 35 Maddox, S. Motorny, P. Henry, D. Richardson, K. Torab, C. Subraveti, M. Johnson, B. Williams and R. 36 Williams for technical advice and assistance. We thank B. Cumming, V. Casagrande, Y. Jiang, and F. 37 Briggs for input and feedback at an early stage of this work. 38 39 40 Abstract 41 The lateral geniculate nucleus (LGN) of the dorsal thalamus is the primary recipient of the two 42 eyes’ outputs. Most LGN neurons are monocular in that they are activated by visual stimulation 43 through only one (dominant) eye. However, there are both intrinsic connections and inputs from 44 binocular structures to the LGN that could provide these neurons with signals originating from 45 the other (non-dominant) eye. Indeed, previous work introducing luminance differences across 46 the eyes or using a single-contrast stimulus showed binocular modulation for single unit activity 47 in anesthetized macaques and multiunit activity in awake macaques. Here, we sought to 48 determine the influence of contrast viewed by both the non-dominant and dominant eyes on LGN 49 single-unit responses in awake macaques. To do this, we adjusted each eye’s signal strength by 50 independently varying the contrast of stimuli presented to the two eyes. Specifically, we 51 recorded LGN single unit spiking activity in two awake macaques while they viewed drifting 52 gratings of varying contrast. We found that LGN neurons of all types (parvo-, magno-, and 53 koniocellular) were significantly suppressed when stimuli were presented at low contrast to the 54 dominant eye and at high contrast to the non-dominant eye. Further, the inputs of the two eyes 55 showed antagonistic interaction, whereby the magnitude of binocular suppression diminished 56 with high contrast in the dominant eye, or low contrast in the non-dominant eye. These results 57 suggest that the LGN represents a site of pre-cortical binocular processing involved in resolving 58 discrepant contrast differences between the eyes. 59 60 61 62 2 63 Significance 64 A fundamental feature of the primate visual system is its binocular arrangement, which affords 65 stereovision and hyperacuity. A consequence of this arrangement is that the two eyes’ views 66 need to be resolved to yield singular vision, which is normally accomplished by fusion or 67 suppression of one of the eye’s inputs. This binocular processing has been shown to occur in 68 cortex, subsequent to thalamic processing. Here, we show that neurons in the lateral geniculate 69 nucleus receiving excitatory retinal input from one eye can be suppressed by high-contrast visual 70 stimulation of the other eye, indicating that the geniculate serves as a pre-cortical site of 71 binocular processing. 72 73 74 75 76 77 78 79 80 81 82 83 3 84 Introduction 85 The lateral geniculate nucleus (LGN) is the main recipient of the outputs of the two eyes 86 in primates. Its anatomical organization raises the question of the role it plays in resolving 87 binocular inputs to support singular vision. In diurnal primates, the LGN comprises distinct 88 layers and virtually all neurons within each layer receive direct inputs from only one eye (Kaas et 89 al., 1972). Neurons within a layer receive input from one eye and neighboring layers contain 90 neurons that receive input from the other eye. Congruent with their inputs, almost all LGN 91 neurons are monocular, exclusively excited by stimulation of one eye. Nevertheless, LGN 92 neurons might interact across layers (Campo-Ortega, Glees, Neuhoff, 1968; Saini and Garey, 93 1981) or receive inputs from structures with binocular neurons (Lund et al., 1975; Hubel and 94 Wiesel, 1968). The effects of these influences could manifest as a difference in magnitude of 95 visual responses under binocular stimulation relative to monocular stimulation. 96 Studies in cats have well-established that spike rates of most LGN neurons are altered by 97 binocular stimulation (Sanderson et al., 1971; Schmielau and Singer, 1977; Xue et al., 1987; 98 Tong et al., 1992; Sengpiel et al., 1995). Binocular modulation also occurs in the primate. Unlike 99 in the cat, related work in macaques has not focused on visual contrast. Instead, previous work 100 on binocular modulation either introduced luminance differences across the eyes (Rodieck and 101 Dreher, 1979; Schroeder et al., 1990) or introduced stimuli at one contrast level (Marrocco and 102 McClurkin, 1979). One reason to address this question in macaques is that cat LGN differs 103 anatomically from primate LGN (reviewed by Dougherty et al., 2018). Assessing binocular 104 modulation in the LGN as a function of visual contrast in both eyes would reveal how 105 interactions between the eyes is influenced by the strength of each eye’s signal. Contrast- 4 106 dependent binocular interactions in the LGN could have implications for known psychophysical 107 phenomena, such as interocular suppression. 108 The primate LGN is composed of three major cell classes—parvocellular (P), 109 magnocellular (M), and koniocellular (K) neurons—with known functional and anatomical 110 distinctions. Known differences in contrast sensitivity among these parallel pathways (Shapley et 111 al., 1981; Derrington and Lennie, 1984; Norton et al., 1988; Lee et al., 1989a; Sclar et al., 1990) 112 as well as their physical distribution could impact whether contrast-dependent binocular 113 interactions occurs for these groups. Based on the studies that assessed general binocular 114 modulation, it remains unclear whether this modulation occurs only for M or both P and M 115 neurons (Marrocco and McClurkin, 1979; Rodieck and Dreher, 1979). Furthermore, whether K 116 neurons, intercalated between different eye-dominant layers, show binocular modulation in 117 macaques is an outstanding question. Recent work in anesthetized marmosets, focusing on K 118 layers, found that about one third of K neurons get excitatory binocular input (Zeater et al., 119 2015), and that most K neurons with excitatory responses to high-contrast stimuli were 120 suppressed by binocular stimulation (Belluccini et al., 2019). A second question is how binocular 121 modulation of single neurons may be impacted by anesthesia, as anesthesia is known to affect 122 binocular processing in this structure (Schroeder et al., 1988). Only one study thus far has 123 considered LGN binocular processing in the awake state (Schroeder et al., 1990). However, these 124 measures were based on population spiking, which could have included spikes from neighboring 125 eye-dominate layers. 126 We sought to determine how visual contrast viewed by both eyes impacts the visual 127 response of LGN neurons receiving direct input from one eye only in awake primates. To do this, 128 we varied the contrast of stimuli shown to the eyes independently to adjust the signal strength 5 129 each eye carries. Two macaques viewed drifting sine-wave gratings presented to one or both 130 eyes while spiking of LGN neurons was recorded with a linear multicontact electrode array.
Load more

Recommended publications
  • The Morphological Basis for Binocular and ON/OFF Convergence in Tree Shrew Striate Cortex
    The Journal of Neuroscience, April 1992, 12(4): 1319-I 334 The Morphological Basis for Binocular and ON/OFF Convergence in Tree Shrew Striate Cortex E. Christopher Muly and David Fitzpatrick Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710 We used retrograde and anterograde transport methods and sponse),reflecting distinct inputs from corresponding popula- single-cell reconstructions to examine the projection from tions of retinal ganglion cells (Kuffler, 1953; Hubel and Wiesel, layer IV to supragranular layers in the tree shrew’s striate 1961). In contrast, single cortical neurons have both ON and cortex. We found that neurons in the ON and OFF subdivi- OFF responsesdue to the convergenceof information conveyed sions of layer IV (IVa and IVb, respectively) have overlapping by ON and OFF center LGN neurons(Hubel and Wiesel, 1962; terminal fields throughout layers II and Ill. Despite their over- Schiller, 1982; Tanaka, 1983; Sherk and Horton, 1984). lap, these projections are organized in a highly stratified, The generation of binocular, dual-sign (ON/OFF) responses mirror-symmetric fashion that respects the vertical position from monocular, single-sign(ON or OFF) responsesmust reflect of neurons within each sublayer. Neurons in the middle of a simple anatomical fact: the axons of four different classesof layer IV (lower IVa and upper IVb) project to layers Ills/b, II, LGN neurons (i.e., ipsilateral ON, ipsilateral OFF, contralateral and I; neurons located at the edges of layer IV (upper IVa ON, and contralateral OFF), or cortical neuronsthat convey the and lower IVb) project to the lower half of layer Illc; and information from theseLGN neurons, synapseon a singlepost- neurons in the middle of IVa and the middle of IVb project synaptic neuron.
    [Show full text]
  • Seeing in Three Dimensions: the Neurophysiology of Stereopsis Gregory C
    Review DeAngelis – Neurophysiology of stereopsis Seeing in three dimensions: the neurophysiology of stereopsis Gregory C. DeAngelis From the pair of 2-D images formed on the retinas, the brain is capable of synthesizing a rich 3-D representation of our visual surroundings. The horizontal separation of the two eyes gives rise to small positional differences, called binocular disparities, between corresponding features in the two retinal images. These disparities provide a powerful source of information about 3-D scene structure, and alone are sufficient for depth perception. How do visual cortical areas of the brain extract and process these small retinal disparities, and how is this information transformed into non-retinal coordinates useful for guiding action? Although neurons selective for binocular disparity have been found in several visual areas, the brain circuits that give rise to stereoscopic vision are not very well understood. I review recent electrophysiological studies that address four issues: the encoding of disparity at the first stages of binocular processing, the organization of disparity-selective neurons into topographic maps, the contributions of specific visual areas to different stereoscopic tasks, and the integration of binocular disparity and viewing-distance information to yield egocentric distance. Some of these studies combine traditional electrophysiology with psychophysical and computational approaches, and this convergence promises substantial future gains in our understanding of stereoscopic vision. We perceive our surroundings vividly in three dimen- lished the first reports of disparity-selective neurons in the sions, even though the image formed on the retina of each primary visual cortex (V1, or area 17) of anesthetized cats5,6.
    [Show full text]
  • Binocular Vision
    BINOCULAR VISION Rahul Bhola, MD Pediatric Ophthalmology Fellow The University of Iowa Department of Ophthalmology & Visual Sciences posted Jan. 18, 2006, updated Jan. 23, 2006 Binocular vision is one of the hallmarks of the human race that has bestowed on it the supremacy in the hierarchy of the animal kingdom. It is an asset with normal alignment of the two eyes, but becomes a liability when the alignment is lost. Binocular Single Vision may be defined as the state of simultaneous vision, which is achieved by the coordinated use of both eyes, so that separate and slightly dissimilar images arising in each eye are appreciated as a single image by the process of fusion. Thus binocular vision implies fusion, the blending of sight from the two eyes to form a single percept. Binocular Single Vision can be: 1. Normal – Binocular Single vision can be classified as normal when it is bifoveal and there is no manifest deviation. 2. Anomalous - Binocular Single vision is anomalous when the images of the fixated object are projected from the fovea of one eye and an extrafoveal area of the other eye i.e. when the visual direction of the retinal elements has changed. A small manifest strabismus is therefore always present in anomalous Binocular Single vision. Normal Binocular Single vision requires: 1. Clear Visual Axis leading to a reasonably clear vision in both eyes 2. The ability of the retino-cortical elements to function in association with each other to promote the fusion of two slightly dissimilar images i.e. Sensory fusion. 3. The precise co-ordination of the two eyes for all direction of gazes, so that corresponding retino-cortical element are placed in a position to deal with two images i.e.
    [Show full text]
  • Dichoptic Visual Masking Reveals That Early Binocular Neurons Exhibit Weak Interocular Suppression: Implications for Binocular Vision and Visual Awareness
    Dichoptic Visual Masking Reveals that Early Binocular Neurons Exhibit Weak Interocular Suppression: Implications for Binocular Vision and Visual Awareness Stephen L. Macknik* and Susana Martinez-Conde* Abstract & Visual masking effects are illusions in which a target is together fail to support models of masking that require rendered invisible by a mask, which can either overlap or not circuits found only in the cortex, but support our proposed overlap the target spatially and/or temporally. These illusions model that suggests that simple ubiquitous lateral inhibition provide a powerful tool to study visibility and consciousness, may itself be the fundamental mechanism that explains visual object grouping, brightness perception, and much more. As masking across multiple levels in the brain. We also show that such, the physiological mechanisms underlying the perception area V1 neurons are dichoptic in terms of excitation, but of masking are critically important to our understanding of monoptic in terms of inhibition. That is, responses within area visibility. Several models that require cortical circuits have been V1 binocular neurons reveal that excitation to monocular proposed previously to explain the mysterious spatial and targets is inhibited strongly only by masks presented to the timing effects associated with visual masking. Here we describe same eye, and not by masks presented to the opposite eye. single-unit physiological experiments from the awake monkey These results lead us to redefine the model for the first stage of that show that visual masking occurs in at least two separate binocular processing in the visual system, and may be crucial to and independent circuits, one that is binocular and one that is interpreting the effects of other similar binocular and dichoptic monocular (possibly even subcortical), without feedback from stimulation paradigms, such as the binocular rivalry family of higher-level visual brain areas.
    [Show full text]
  • Development of Binocular Vision in the Kitten's Striate Cortex
    The Journal of Neuroscience, December 1992, fZ(12): 4721-4736 Development of Binocular Vision in the Kitten’s Striate Cortex Ralph D. Freeman and lzumi Ohzawa Group in Neurobiology, School of Optometry, University of California at Berkeley, Berkeley, California 94720 Studies of the development and plasticity of the visual path- factors may be applicable. In any case, although major re- way are well documented, but a basic question remains open: finements occur in stereoscopic vision postnatally, the what is the physiological status of the system prior to ex- physiological connections that underlie this function are tensive visual experience? Somewhat conflicting answers operational at a very early postnatal age. have been put forward, and in a major area, binocular vision, reports have ranged from severe immaturity to well-devel- The development and plasticity of visual function has been oped maturity. This is an important question to resolve since studied extensively by useof behavioral, physiological, anatom- binocular cells in the visual cortex are thought to be the ical, and neurochemical approaches.This work has engendered neural substrate for stereoscopic depth perception. a considerable literature, which is reviewed in several articles We have addressed this question by recording from single (see,e.g., Fregnecand Imbert, 1984; Mitchell and Timney, 1984). cells in the striate cortex of kittens at postnatal ages 2, 3, In order to understand the limits and rules of plasticity, one and 4 weeks and from adults for comparison. Gratings with requires firm knowledge of normal visual functions at various sinusoidal luminance distribution are presented to left, right, stagesof development. By far the most studied animal in this or both eyes.
    [Show full text]
  • Binocular Process in Human Vision BRIAN TIMNEY, LAURIE M
    On the evidence for a 'pure' binocular process in human vision BRIAN TIMNEY, LAURIE M. WILCOX and ROBERT ST. JOHN* Department of Psychology, University of Western Ontario, London, Ontario, Canada N6A 5C2 Received13 October 1987;accepted 28 February 1989 Abstract-Wolfe (1986,Psychol. Rev. 93, 269-282)proposed a model of human binocular vision based on the assumption of two functionallydistinct classesof binocular neuron. These neurons may be regarded as logicalAND and OR gates.In the present paper we assessthe evidencerelevant to this assumption.We find that whileboth types of binocular neuron have been describedin the cortex of cat and monkey,there is no indicationthat they form functionallyseparate populations.Critical analysis of the psychophysicalevidence for AND and OR channelsin human vision suggeststhat much of the data presentedin favor of an AND channelis subject to alternativeinterpretations. We concludethat the availabledata are not consistentwith the existenceof separate channels as proposed by Wolfe. INTRODUCTION In a recent paper, Wolfe (1986) proposed a model of human binocular vision that attempted to integrate the mechanisms of stereopsis and binocular rivalry. His model depends critically upon two functionally distinct classes of binocular neuron. The neurons of one class may be described as logical AND gates. They can be activated only through simultaneous stimulation of both eyes and are assumed to play a major role in stereopsis. Neurons in the second class may be considered as OR gates. They can be stimulated through either eye and are assumed to play a major role in binocular rivalry. The OR neurons are considered to be secondary to the AND cells in the mediation of stereopsis.
    [Show full text]
  • THE PHYSIOLOGY of STEREOPSIS B. G. Cumming G. C. Deangelis
    P1: FUI January 16, 2001 9:19 Annual Reviews AR121-08 Annu. Rev. Neurosci. 2001. 24:203–38 Copyright c 2001 by Annual Reviews. All rights reserved THE PHYSIOLOGY OF STEREOPSIS B. G. Cumming University Laboratory of Physiology, Oxford, OX1 3PT,1 United Kingdom; e-mail: [email protected] G. C. DeAngelis Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110-1093; e-mail: [email protected] Key Words binocular vision, disparity, striate cortex, extrastriate cortex, depth perception ■ Abstract Binocular disparity provides the visual system with information con- cerning the three-dimensional layout of the environment. Recent physiological studies in the primary visual cortex provide a successful account of the mechanisms by which single neurons are able to signal disparity. This work also reveals that additional pro- cessing is required to make explicit the types of signal required for depth perception (such as the ability to match features correctly between the two monocular images). Some of these signals, such as those encoding relative disparity, are found in ex- trastriate cortex. Several other lines of evidence also suggest that the link between perception and neuronal activity is stronger in extrastriate cortex (especially MT) than in the primary visual cortex. INTRODUCTION A central problem faced by the visual system is providing information about a three-dimensional environment from two-dimensional retinal images. In many animals, one of the most precise sources of information arises from the fact that the two eyes have different vantage points. This means that the images on the two retinae are not identical (see Figure 1).
    [Show full text]
  • Modelling Binocular Neurons in the Primary Visual Cortex
    Mo delling Bino cular Neurons in the Primary Visual Cortex David J Fleet David J Heeger Hermann Wagner Intro duction Neurons sensitive to bino cular disparityhave b een found in the visual cortex of many mammals and in the visual wulst of the owl and are thought to play a signicant role in stereopsis Barlow et al Nikara et al Hub el and Wiesel Clarke et al Pettigrew and Konishi Poggio and Fischer Fischer and Kruger Ferster Poggio and Talb ot OhzawaandFreeman a Ohzawa and Freeman b LeVayandVoigt Ohzawa et al DeAngelis et al Wagner and Frost A number of physiologists have suggested that disparity might b e enco ded by a shift of receptiveeld p osition Hub el and Wiesel Pettigrew et al Pettigrew Maske et al Poggio et al Wagner and Frost According to this p ositionshift mo del disparity selective cells combine the outputs of similarly shap ed mono cular receptive elds from dierent retinal p ositions in the left and righteyes More recently Ohzawa et al and DeAngelis et al have suggested that disparity sensitivity might instead b e a result of intero cular phase shifts In this phaseshift mo del the centers of the left and righteye receptive elds coincide but the arrangement of receptive eld subregions is dierent This chapter presents a formal description and analysis of a bino cular energy mo del of disparity selectivity According to this mo del disparity selectivity results from a combination of p ositionshifts andor phaseshifts Our theoretical analysis suggests how one might p erform an exp eriment
    [Show full text]
  • Theory for the Development of Neuron Selectivity: Orientation Specificity and Binocular Interaction in Visual Cortex1
    0270~6474/82/0201-0032$02.00/O The Journal of Neuroscience Copyright 0 Society for Neuroscience Vol. 2, No. 1, pp. 32-48 Printed in U.S.A. January 1982 THEORY FOR THE DEVELOPMENT OF NEURON SELECTIVITY: ORIENTATION SPECIFICITY AND BINOCULAR INTERACTION IN VISUAL CORTEX1 ELIE L. BIENENSTOCK,2 LEON N COOPER,3 AND PAUL W. MUNRO Center for Neural Science, Department of Physics, and Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912 Received June 5, 1981; Revised August 27, 1981; Accepted September 1, 1981 Abstract The development of stimulus selectivity in the primary sensory cortex of higher vertebrates is considered in a general mathematical framework. A synaptic evolution scheme of a new kind is proposed in which incoming patterns rather than converging afferents compete. The change in the efficacy of a given synapse depends not only on instantaneous pre- and postsynaptic activities but also on a slowly varying time-averaged value of the postsynaptic activity. Assuming an appropriate nonlinear form for this dependence, development of selectivity is obtained under quite general conditions on the sensory environment. One does not require nonlinearity of the neuron’s integrative power nor does one need to assume any particular form for intracortical circuitry. This is first illustrated in simple cases, e.g., when the environment consists of only two different stimuli presented alternately in a random manner. The following formal statement then holds: the state of the system converges with probability 1 to points of maximum selectivity in the state space. We next consider the problem of early development of orientation selectivity and binocular interaction in primary visual cortex.
    [Show full text]
  • Adaptation to Binocular Anticorrelation Results in Increased Neural Excitability
    Adaptation to Binocular Anticorrelation Results in Increased Neural Excitability Reuben Rideaux, Elizabeth Michael, and Andrew E. Welchman Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/32/1/100/1861419/jocn_a_01471.pdf by guest on 05 May 2021 Abstract ■ Throughout the brain, information from individual sources Receptive fields of disparity-tuned simple cells in macaque V1. converges onto higher order neurons. For example, information Neuron, 38,103–114, 2003; Cumming, B. G., & Parker, A. J. from the two eyes first converges in binocular neurons in area V1. Responses of primary visual cortical neurons to binocular dispar- Downloaded from http://direct.mit.edu/jocn/article-pdf/32/1/100/1931154/jocn_a_01471.pdf by guest on 26 September 2021 Some neurons are tuned to similarities between sources of infor- ity without depth perception. Nature, 389, 280–283, 1997], their mation, which makes intuitive sense in a system striving to match function has remained opaque. To determine how neural mech- multiple sensory signals to a single external cause—that is, estab- anisms tuned to dissimilarities support perception, here we use lish causal inference. However, there are also neurons that are electroencephalography to measure human observers’ steady- tuned to dissimilar information. In particular, some binocular neu- state visually evoked potentials in response to change in depth rons respond maximally to a dark feature in one eye and a light after prolonged viewing of anticorrelated and correlated feature in the other. Despite compelling neurophysiological and random-dot stereograms (RDS). We find that adaptation to an- behavioral evidence supporting the existence of these neurons ticorrelated RDS results in larger steady-state visually evoked [Katyal, S., Vergeer, M., He, S., He, B., & Engel, S.
    [Show full text]
  • Innervation Patterns of Single Physiologically Identified
    Proc. Nail. Acad. Sci. USA Vol. 87, pp. 449-453, January 1990 Neurobiology Innervation patterns of single physiologically identified geniculocortical axons in the striate cortex of the tree shrew (geniculocortical afferents/visual cortex/on- and off-center pathways/binocular convergence) DAVID FITZPATRICK* AND DENiS RACZKOWSKI Department of Neurobiology, Duke University, Durham, NC 27710 Communicated by Irving T. Diamond, October 10, 1989 ABSTRACT We examined the termination patterns of MATERIALS AND METHODS single geniculocortical axons in the striate cortex of the tree shrew by using intracellular recording and horseradish per- We obtained the data for this report from adult tree shrews oxidase staining methods. Axons were classified by whether raised in our breeding colony. At the outset ofan experiment, they responded to light onset (ON center) or light offset (OFF we anesthetized the tree shrew with ketamine and xylazine, center) and whether they were driven by the ipsi- or contra- cannulated a vein for infusion of a dextrose/saline solution lateral eye. Afferents with ON-center responses end in the containing sodium thiopental (delivered at a rate of 3 upper part oflayer IV (IVa) whereas afferents with OFF-center mgkg-1hr-1 for the remainder of the experiment), per- responses end in the lower part of layer IV (IVb). Within each formed a tracheotomy, and placed a catheter in the bladder. tier, axons driven by the ipsilateral and contralateral eye The animal was placed in a stereotaxic apparatus, paralyzed overlap. These results suggest that binocular convergence with pancuronium bromide to prevent eye movements and occurs within layer IV without mixing the information from the ventilated with a respirator to maintain expired CO2 between ON- and OFF-center pathways and we consider the significance 2 and 3%.
    [Show full text]
  • Lecture 6 Depth Perception
    6 Space Perception and Binocular Vision Chapter 6 Space Perception and Binocular Vision Monocular Cues to Three-Dimensional Space Binocular Vision and Stereopsis Combining Depth Cues Development of Binocular Vision and Stereopsis Introduction Realism: The external world exists. Positivists: The world depends on the evidence of the senses; it could be a hallucination! • This is an interesting philosophical position, but for the purposes of this course, let’s just assume the world exists. Introduction Euclidian geometry: Parallel lines remain parallel as they are extended in space. • Objects maintain the same size and shape as they move around in space. • Internal angles of a triangle always add up to 180 degrees, etc. Introduction Notice that images projected onto the retina are non-Euclidean! • Therefore, our brains work with non- Euclidean geometry all the time, even though we are not aware of it. Figure 6.1 The Euclidean geometry of the three-dimensional world turns into something quite different on the curved, two-dimensional retina Introduction Probability summation: The increased probability of detecting a stimulus from having two or more samples. • One of the advantages of having two eyes that face forward. Introduction Binocular summation: The combination (or “summation”) of signals from each eye in ways that make performance on many tasks better with both eyes than with either eye alone. The two retinal images of a three- dimensional world are not the same! Figure 6.2 The two retinal images of a three-dimensional world are not the same Introduction Binocular disparity: The differences between the two retinal images of the same scene.
    [Show full text]