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Kremers J, Aher AJ, Parry NRA, Patel NB, Frishman LJ. Comparison of macaque and human L- and M-cone driven electroretinograms. Exp Eye Res 2021; 206:108556. [PMID: 33794198 DOI: 10.1016/j.exer.2021.108556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 03/05/2021] [Accepted: 03/22/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE The macaque retina is often used as a model for the human retina. However, there are only a handful of direct in vivo comparisons of the retinal physiology in humans and macaques. In the current study, ERG responses to luminance, L-cone isolating and M-cone isolating stimuli with sinusoidal, sawtooth and square wave temporal profiles were measured. The results were compared with those obtained from human observers. METHODS The responses from five anesthetized adult macaques were measured. Full field stimuli were created. L- and M-cone isolating stimuli were based on the triple silent substitution technique. Sinusoidal stimuli had temporal frequencies between 4 and 56 Hz in 4 Hz steps. Sawtooth stimuli with rapid-on ramp-off and with rapid-off ramp-on excitation profiles had a frequency of 4 Hz. Square stimuli were presented at 2 Hz. RESULTS Macaque and human ERGs in response to L- and M-cone isolating stimuli reflect L/M opponency and luminance activity. In responses to sine waves, cone opponency dominates at low temporal frequencies (4-12 Hz); luminance dominates at high temporal frequencies. The responses to sawtooth and square wave stimuli reflect a mixture of chromatic and luminance activity. L:M response ratios vary between individuals both in macaques and humans. Macaques show more complex responses, including greater second harmonic contributions than those in humans. CONCLUSIONS Macaque and human ERGs share basic underlying mechanisms reflecting L/M opponency and luminance activity. There may be quantitative differences possibly reflecting differences in contributions of inner retinal mechanisms to the ERGs.
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Affiliation(s)
- Jan Kremers
- Section for Retinal Physiology, University Hospital Erlangen, 91054, Erlangen, Germany.
| | - Avinash J Aher
- Section for Retinal Physiology, University Hospital Erlangen, 91054, Erlangen, Germany
| | - Neil R A Parry
- Vision Science Centre, Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK; Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Nimesh B Patel
- Department of Vision Sciences, College of Optometry, University of Houston, Houston, TX, USA
| | - Laura J Frishman
- Department of Vision Sciences, College of Optometry, University of Houston, Houston, TX, USA
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Tootell RBH, Nasr S. Scotopic Vision Is Selectively Processed in Thick-Type Columns in Human Extrastriate Cortex. Cereb Cortex 2021; 31:1163-1181. [PMID: 33073288 PMCID: PMC7786355 DOI: 10.1093/cercor/bhaa284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 07/25/2020] [Accepted: 08/17/2020] [Indexed: 11/26/2022] Open
Abstract
In humans, visual stimuli can be perceived across an enormous range of light levels. Evidence suggests that different neural mechanisms process different subdivisions of this range. For instance, in the retina, stimuli presented at very low (scotopic) light levels activate rod photoreceptors, whereas cone photoreceptors are activated relatively more at higher (photopic) light levels. Similarly, different retinal ganglion cells are activated by scotopic versus photopic stimuli. However, in the brain, it remains unknown whether scotopic versus photopic information is: 1) processed in distinct channels, or 2) neurally merged. Using high-resolution functional magnetic resonance imaging at 7 T, we confirmed the first hypothesis. We first localized thick versus thin-type columns within areas V2, V3, and V4, based on photopic selectivity to motion versus color, respectively. Next, we found that scotopic stimuli selectively activated thick- (compared to thin-) type columns in V2 and V3 (in measurements of both overlap and amplitude) and V4 (based on overlap). Finally, we found stronger resting-state functional connections between scotopically dominated area MT with thick- (compared to thin-) type columns in areas V2, V3, and V4. We conclude that scotopic stimuli are processed in partially segregated parallel streams, emphasizing magnocellular influence, from retina through middle stages of visual cortex.
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Affiliation(s)
- Roger B H Tootell
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
| | - Shahin Nasr
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
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Souza GS, Malone FL, Crawford TL, Miquilini L, Salomão RC, Guimarães DL, Ventura DF, Fitzgerald MEC, Silveira LCL. Low number of luminance levels in the luminance noise increases color discrimination thresholds estimated with pseudoisochromatic stimuli. Front Psychol 2015; 5:1291. [PMID: 25566106 PMCID: PMC4274881 DOI: 10.3389/fpsyg.2014.01291] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 10/24/2014] [Indexed: 11/13/2022] Open
Abstract
In pseudoisochromatic stimuli the presence of spatial and luminance noise forces the subject to discriminate the target from the background solely on the basis of chromaticity difference. Color-blind subjects may show difficulty to identify the target due to the elimination of borders and brightness clues caused by the luminance and spatial noise. Few studies have fully described the features of pseudoisochromatic stimuli. Fewer investigators have focused their studies in the effects of specific pseudoisochromatic parameters on color discrimination. We used the Cambridge Color Test (CCT) to investigate the influence on color discrimination thresholds due to the number of luminance levels present in the luminance noise. The CCT default has six luminance steps; however, in our investigation a total of eight different conditions were tested from 2 to 16 luminance steps. It was found that the CCT provided very robust values for color discrimination thresholds, which were degraded only for very small number of luminance steps. When the number of steps was increased, the color discrimination thresholds improved from 2 to 6 luminance steps and gradually reached a plateau for 10 or more luminance steps. The area of color discrimination ellipses as a function of luminance steps matches the relative proportion of ineffective contrasts between mosaic patches as a function of luminance steps, assuming that contrast becomes ineffective for values 18.6% or less. The lower number of color and luminance interactions in these conditions could explain the measured increase of color discrimination thresholds. The primary conclusion from this investigation was that results from pseudoisochromatic tests should have their parameters described in more detail. This type of description would allow a better understanding of the results provided, interpretations, and therefore cross study comparison of results obtained from different laboratories.
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Affiliation(s)
- Givago S Souza
- Instituto de Ciências Biológicas, Universidade Federal do Pará Belém, Brazil ; Núcleo de Medicina Tropical, Universidade Federal do Pará Belém, Brazil
| | | | - Teera L Crawford
- College of Medicine, University of Tennessee Health Science Center Memphis, TN, USA
| | - Letícia Miquilini
- Instituto de Ciências Biológicas, Universidade Federal do Pará Belém, Brazil
| | - Raílson C Salomão
- Instituto de Ciências Biológicas, Universidade Federal do Pará Belém, Brazil
| | - Diego L Guimarães
- Instituto de Ciências Biológicas, Universidade Federal do Pará Belém, Brazil
| | - Dora F Ventura
- Instituto de Psicologia, Universidade de São Paulo São Paulo, Brazil
| | - Malinda E C Fitzgerald
- Department of Biology, University of Memphis Memphis, TN, USA ; Department of Anatomy and Neurobiology, University of Tennessee Health Science Center Memphis, TN, USA
| | - Luiz Carlos L Silveira
- Instituto de Ciências Biológicas, Universidade Federal do Pará Belém, Brazil ; Núcleo de Medicina Tropical, Universidade Federal do Pará Belém, Brazil
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Formankiewicz MA, Mollon JD. The psychophysics of detecting binocular discrepancies of luminance. Vision Res 2009; 49:1929-38. [PMID: 19460400 DOI: 10.1016/j.visres.2009.05.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 05/06/2009] [Accepted: 05/08/2009] [Indexed: 12/01/2022]
Abstract
In the natural world, a binocular discrepancy of luminance can signal a glossy surface. Using a spatial forced choice task, we have measured the ability of subjects to detect binocular luminance disparities. We show that the detection of binocular luminance disparity shares several basic psychophysical features with the detection of surface properties such as lightness and chromaticity: an approximation to Weber's Law, spatial summation, temporal summation, and a deterioration with increasing eccentricity. We also discuss whether color-deficient subjects could derive reliable information about chromaticity from the binocular disparities of luminance induced by a monocularly worn color filter.
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Affiliation(s)
- Monika A Formankiewicz
- Anglia Vision Research, Department of Optometry and Ophthalmic Dispensing, Anglia Ruskin University, Cambridge CB11PT, United Kingdom.
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Lebedev DS, Marshak DW. Amacrine cell contributions to red-green color opponency in central primate retina: a model study. Vis Neurosci 2007; 24:535-47. [PMID: 17900377 PMCID: PMC3348784 DOI: 10.1017/s0952523807070502] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Accepted: 05/01/2007] [Indexed: 11/06/2022]
Abstract
To investigate the contributions of amacrine cells to red-green opponency, a linear computational model of the central macaque retina was developed based on a published cone mosaic. In the model, amacrine cells of ON and OFF types received input from all neighboring midget bipolar cells of the same polarity, but OFF amacrine cells had a bias toward bipolar cells whose center responses were mediated by middle wavelength sensitive cones. This bias might arise due to activity dependent plasticity because there are midget bipolar cells driven by short wavelength sensitive cones in the OFF pathway. The model midget ganglion cells received inputs from neighboring amacrine cells of both types. As in physiological experiments, the model ganglion cells showed spatially opponent responses to achromatic stimuli, but they responded to cone isolating stimuli as though center and surround were each driven by a single cone type. Without amacrine cell input, long and middle wavelength sensitive cones contributed to both the centers and surrounds of model ganglion cell receptive fields. According to the model, the summed amacrine cell input was red-green opponent even though inputs to individual amacrine cells were unselective. A key prediction is that GABA and glycine depolarize two of the four types of central midget ganglion cells; this may reflect lower levels of the potassium chloride co-transporter in their dendrites.
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Affiliation(s)
- D S Lebedev
- Laboratory of Sensory Information Processing, Institute for Information Transmission Problems, Moscow, Russia
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Schechter I, Butler PD, Jalbrzikowski M, Pasternak R, Saperstein AM, Javitt DC. A new dimension of sensory dysfunction: stereopsis deficits in schizophrenia. Biol Psychiatry 2006; 60:1282-4. [PMID: 16945346 PMCID: PMC2901805 DOI: 10.1016/j.biopsych.2006.03.064] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Revised: 03/23/2006] [Accepted: 03/28/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND Schizophrenia is a neurocognitive disorder with a wide range of cognitive and sensory impairments. Early visual processing has been shown to be especially impaired. This article investigates the integrity of binocular depth perception (stereopsis) in schizophrenia. METHODS Seventeen schizophrenia patients and 19 healthy control subjects were compared on the Graded Circles Stereo Test. Results of stereoacuity were compared between patients and control subjects using t test. RESULTS Schizophrenia patients demonstrated significantly (p = .006) reduced stereoacuity (mean = 142 arcseconds) versus control subjects (mean = 55 arcseconds). At the normative level for adults, patients performed below chance. CONCLUSIONS These findings demonstrate an impairment of binocular depth perception and further confirm deficits of early visual processing in schizophrenia. Findings are discussed in context of magnocellular/dorsal stream processing with implications for visual processing and cognitive deficits.
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Affiliation(s)
- Isaac Schechter
- Program in Cognitive Neuroscience and Schizophrenia, Nathan Kline Institute for Psychiatric Research, Orangeburg, New York 10962, USA.
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Schechter I, Butler PD, Zemon VM, Revheim N, Saperstein AM, Jalbrzikowski M, Pasternak R, Silipo G, Javitt DC. Impairments in generation of early-stage transient visual evoked potentials to magno- and parvocellular-selective stimuli in schizophrenia. Clin Neurophysiol 2005; 116:2204-15. [PMID: 16055375 PMCID: PMC2901806 DOI: 10.1016/j.clinph.2005.06.013] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2004] [Revised: 06/06/2005] [Accepted: 06/11/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Patients with schizophrenia demonstrate significant impairments of early visual processing, potentially implicating dysfunction of the magnocellular visual pathway. The present study evaluates transient visual evoked potential (tVEP) responses to stimuli biased toward the magnocellular (M) or parvocellular (P) systems in patients with schizophrenia vs. normal volunteers first to evaluate relative contributions of M and P systems to specific tVEP components in schizophrenia and, second, to evaluate integrity of early M and P processing in schizophrenia. METHODS Seventy-four patients with schizophrenia and schizoaffective disorder were compared with 59 control subjects using separate stimuli to assess the tVEP response to M, P and mixed M/P conditions. Stimuli were biased toward M vs. P processing by manipulation of chromatic and achromatic contrast. C1, P1, N1 and P2 components were compared between patients and controls. All subjects showed 20/32 vision or better. RESULTS Waveforms were obtained to low contrast (M), chromatic contrast (P) and high contrast (mixed M/P) stimuli in both patients and controls. C1 was present to P and mixed M/P stimuli. Patients showed a significant reduction in amplitude and an increase in latency of the C1 component. P1 was elicited primarily by M and mixed M/P stimuli, whereas N1 was elicited primarily by P and mixed M/P stimuli. Patients showed reductions in both P1 and N1 amplitudes across conditions. However, only reductions in P1 amplitude survived covariation for between group differences in visual acuity. Further, P1 amplitude reductions in the M condition correlated with a proxy measure of global outcome. CONCLUSIONS M- and P-selective stimuli elicit differential components of the tVEP. Patients with schizophrenia show significant reductions in response even to simple visual stimuli. Deficits, particularly within the M system, may correlate significantly with global outcome and level of community functioning. SIGNIFICANCE Whereas deficits in high-order cognitive processing have been extensively documented in schizophrenia, integrity of early-stage sensory processing has been studied to a lesser degree. The present findings suggest that deficits in early-stage visual processing are significantly related to overall clinical outcome in schizophrenia. Further, between-group differences in visual acuity may influence VEP results, even for subjects with 'normal' vision (20/32 or better).
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Affiliation(s)
- Isaac Schechter
- Nathan Kline Institute, Program in Cognitive Neuroscience and Schizophrenia, Orangeburg, NY, USA
| | - Pamela D. Butler
- Nathan Kline Institute, Program in Cognitive Neuroscience and Schizophrenia, Orangeburg, NY, USA
- New York University School of Medicine, New York, NY, USA
- Corresponding author. Address: Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA. Tel.: +1 845 398 6537; fax: +1 845 398 6545. E-mail address: (P.D. Butler)
| | - Vance M. Zemon
- Nathan Kline Institute, Program in Cognitive Neuroscience and Schizophrenia, Orangeburg, NY, USA
- Ferkauf Graduate School of Psychology, Yeshiva University, Bronx, NY, USA
| | - Nadine Revheim
- Nathan Kline Institute, Program in Cognitive Neuroscience and Schizophrenia, Orangeburg, NY, USA
| | - Alice M. Saperstein
- Nathan Kline Institute, Program in Cognitive Neuroscience and Schizophrenia, Orangeburg, NY, USA
| | - Maria Jalbrzikowski
- Nathan Kline Institute, Program in Cognitive Neuroscience and Schizophrenia, Orangeburg, NY, USA
| | - Roey Pasternak
- Nathan Kline Institute, Program in Cognitive Neuroscience and Schizophrenia, Orangeburg, NY, USA
| | - Gail Silipo
- Nathan Kline Institute, Program in Cognitive Neuroscience and Schizophrenia, Orangeburg, NY, USA
| | - Daniel C. Javitt
- Nathan Kline Institute, Program in Cognitive Neuroscience and Schizophrenia, Orangeburg, NY, USA
- New York University School of Medicine, New York, NY, USA
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Johnson EN, Hawken MJ, Shapley R. The spatial transformation of color in the primary visual cortex of the macaque monkey. Nat Neurosci 2001; 4:409-16. [PMID: 11276232 DOI: 10.1038/86061] [Citation(s) in RCA: 231] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Perceptually, color is used to discriminate objects by hue and to identify color boundaries. The primate retina and the lateral geniculate nucleus (LGN) have cell populations sensitive to color modulation, but the role of the primary visual cortex (V1) in color signal processing is uncertain. We re-evaluated color processing in V1 by studying single-neuron responses to luminance and to equiluminant color patterns equated for cone contrast. Many neurons respond robustly to both equiluminant color and luminance modulation (color-luminance cells). Also, there are neurons that prefer luminance (luminance cells), and a few neurons that prefer color (color cells). Surprisingly, most color-luminance cells are spatial-frequency tuned, with approximately equal selectivity for chromatic and achromatic patterns. Therefore, V1 retains the color sensitivity provided by the LGN, and adds spatial selectivity for color boundaries.
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Affiliation(s)
- E N Johnson
- Center for Neural Science, New York University, 4 Washington Place, New York, New York 10003, USA.
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Gur M, Akri V. Isoluminant stimuli may not expose the full contribution of color to visual functioning: spatial contrast sensitivity measurements indicate interaction between color and luminance processing. Vision Res 1992; 32:1253-62. [PMID: 1455700 DOI: 10.1016/0042-6989(92)90220-d] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Visual performance is greatly impaired when tested with heterochromatic isoluminant stimuli. It is thus concluded that the chromatic system contribution to many visual tasks is limited. We suggest that unless color and luminance are shown to be processed independently, such experiments do not demonstrate shortcomings of the chromatic system but rather the inadequacy of using isoluminant stimuli for isolating that system. We hypothesize that color vision has evolved not only to encode color per se but also to enhance luminance-based visual processing, so that for color information to be fully effective, luminance as well as chromatic variations should be present in the stimulus. The hypothesis was tested by studying the contribution of color to spatial vision. The human contrast sensitivity function (CSF) was studied using luminance, isoluminance (color) and combined luminance/color sinusoidal gratings. It is found that luminance contrast sensitivity is enhanced when luminance contrast is accompanied by color contrast and vice versa. The nature of the interaction is best described by an additive single analyzer model. Color opponent cells which respond to both chromatic and achromatic stimuli may be identified as the analyzer.
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Affiliation(s)
- M Gur
- Department of Biomedical Engineering, Technion, Haifa, Israel
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Abstract
The dependence of grating induction magnitude on retinal illuminance was examined in two subjects. Grating induction magnitude, as determined using the cancellation technique of McCourt, declines monotonically with decreasing retinal illuminance, effectively disappearing at a value of 0.3-0.5 phot td. In a second experiment, sensitivity differences for test lights of 500 and 600 nm were measured as a function of background illuminance in order to gauge the luminance operating range for grating induction with respect to duplex photoreceptor function. Cancelling contrast (and hence grating induction magnitude) fell below detection threshold contrast at retinal illuminances coinciding with the transition from photopic to scotopic visual function. In a third experiment, spatial contrast sensitivity was measured using both spatially extended (10 degrees) and truncated (2 degrees) sinewave gratings at frequencies below 2 c/deg, at three values of retinal illuminance. Illuminance values corresponded to those where grating induction magnitude was, as determined from the first experiment, either maximal, intermediate or negligible. Similar to grating induction, the strength of lateral inhibition, as indexed by the slope of the low-frequency decline in contrast sensitivity, is progressively reduced with decreasing retinal illuminance, particularly for the 2 degree field. There was, however, using the same criteria, evidence of lateral inhibition at a value of retinal illuminance which did not support grating induction. The implications of these results are discussed with respect to classical brightness contrast phenomena, recent neuroanatomical and neurophysiological evidence of segregated parvo- and magnocellular mediated contrast processing systems, and with results from previous studies of the grating induction effect.
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Affiliation(s)
- M E McCourt
- Department of Psychology, University of Texas, Austin 78712
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