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Shapley R, Nunez V, Gordon J. Low luminance contrast's effect on the color appearance of S-cone patterns. Vision Res 2024; 222:108448. [PMID: 38906035 DOI: 10.1016/j.visres.2024.108448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 06/03/2024] [Accepted: 06/05/2024] [Indexed: 06/23/2024]
Abstract
There is a surprisingly strong effect on color appearance when low levels of luminance contrast are added to visual targets in which only S-cones are modulated. This phenomenon can be studied with checkerboard patterns composed of alternating S-cone-modulated checks and gray checks. + S checks look purple when surrounded by slightly brighter gray checks but look highly desaturated (lavender, almost white) when surrounded by darker gray checks. -S checks change in hue with luminance contrast; they look yellow when surrounded by darker gray checks but are greener when surrounded by lighter checks. Psychophysical paired comparisons confirm these perceptions. Furthermore, visual evoked potentials (VEPs) recorded from human posterior cortex indicate that signals evoked by low luminance contrast interact nonlinearly with S-cone-evoked signals in early cortical color processing. Our new psychophysics and electrophysiology results prove that human perception of color appearance is not based on neural computations within a separate, isolated color system. Rather, signals evoked by color contrast and luminance contrast interact to produce the colors we see.
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2
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Sun SH, Killian NJ, Pezaris JS. More than expected: extracellular waveforms and functional responses in monkey LGN. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.22.568065. [PMID: 38798485 PMCID: PMC11118448 DOI: 10.1101/2023.11.22.568065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Unlike the exhaustive determination of cell types in the retina, key populations in the lateral geniculate nucleus of the thalamus (LGN) may have been missed. Here, we have begun to characterize the full range of extracellular neuronal responses in the LGN of awake monkeys using multi-electrodes during the presentation of colored noise visual stimuli to identify any previously overlooked signals. Extracellular spike waveforms of single units were classified into seven distinct classes, revealing previously unrecognized diversity: four negative-dominant classes that were narrow or broad, one triphasic class, and two positive-dominant classes. Based on their mapped receptive field (RF), these units were further categorized into either magnocellular (M), parvocellular (P), koniocellular (K), or non-RF (N). We found correlations between spike shape and mapped RF and response characteristics, with negative and narrow spiking waveform units predominantly associated with P and N RFs, and positive waveforms mostly linked to M RFs. Responses from positive waveforms exhibited shorter latencies, larger RF sizes, and were associated with larger eccentricities in the visual field than the other waveform classes. Additionally, N cells, those without an estimated RF, were consistently responsive to the visually presented mapping stimulus at a lower and more sustained rate than units with an RF. These findings suggest that the LGN cell population may be more diverse than previously believed.
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Affiliation(s)
- Shi Hai Sun
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
- Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
| | - Nathaniel J Killian
- Department of Neurological Surgery, Albert Einstein College of Medicine, Bronx, NY, USA
| | - John S Pezaris
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
- Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
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3
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Rucker F, Taylor C, Kaser-Eichberger A, Schroedl F. Parasympathetic and sympathetic control of emmetropization in chick. Exp Eye Res 2023; 232:109508. [PMID: 37230289 PMCID: PMC10452042 DOI: 10.1016/j.exer.2023.109508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 05/04/2023] [Accepted: 05/15/2023] [Indexed: 05/27/2023]
Abstract
Emmetropization can be altered by temporal visual stimulation and the spectral properties of the visual environment. The goal of the current experiment is to test the hypothesis that there is an interaction between these properties and autonomic innervation. For that purpose, selective lesions of the autonomic nervous system were performed in chickens followed by temporal stimulation. Parasympathetic lesioning involved transection of both the ciliary ganglion and the pterygopalatine ganglion (PPG_CGX; n = 38), while sympathetic lesioning involved transection of the superior cervical ganglion (SCGX; n = 49). After one week of recovery, chicks were then exposed to temporally modulated light (3 days, 2 Hz, Mean: 680 lux) that was either achromatic (with blue [RGB], or without blue [RG]), or chromatic (with blue [B/Y] or without blue [R/G]). Control birds with lesions, or unlesioned, were exposed to white [RGB] or yellow [RG] light. Ocular biometry and refraction (Lenstar and a Hartinger refractometer) was measured before and after exposure to light stimulation. Measurements were statistically analyzed for the effects of a lack of autonomic input and the type of temporal stimulation. In PPG_CGX lesioned eyes, there was no effect of the lesions one-week post-surgery. However, after exposure to achromatic modulation, the lens thickened (with blue) and the choroid thickened (without blue) but there was no effect on axial growth. Chromatic modulation thinned the choroid with R/G. In the SGX lesioned eye, there was no effect of the lesion 1-week post-surgery. However, after exposure to achromatic modulation (without blue), the lens thickened and there was a reduction in vitreous chamber depth and axial length. Chromatic modulation caused a small increase in vitreous chamber depth with R/G. Both autonomic lesion and visual stimulation were necessary to affect the growth of ocular components. The bidirectional responses observed in axial growth and in choroidal changes suggest that autonomic innervation combined with spectral cues from longitudinal chromatic aberration may provide a mechanism for homeostatic control of emmetropization.
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Affiliation(s)
- Frances Rucker
- New England College of Optometry, 424 Beacon St., Boston, MA, 02115, USA.
| | - Chris Taylor
- New England College of Optometry, 424 Beacon St., Boston, MA, 02115, USA
| | - Alexandra Kaser-Eichberger
- Center for Anatomy and Cell Biology, Institute of Anatomy and Cell Biology - Salzburg Paracelsus Medical University, Salzburg, Austria
| | - Falk Schroedl
- Center for Anatomy and Cell Biology, Institute of Anatomy and Cell Biology - Salzburg Paracelsus Medical University, Salzburg, Austria
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4
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Kim YJ, Packer O, Pollreisz A, Martin PR, Grünert U, Dacey DM. Comparative connectomics reveals noncanonical wiring for color vision in human foveal retina. Proc Natl Acad Sci U S A 2023; 120:e2300545120. [PMID: 37098066 PMCID: PMC10160961 DOI: 10.1073/pnas.2300545120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/31/2023] [Indexed: 04/26/2023] Open
Abstract
The Old World macaque monkey and New World common marmoset provide fundamental models for human visual processing, yet the human ancestral lineage diverged from these monkey lineages over 25 Mya. We therefore asked whether fine-scale synaptic wiring in the nervous system is preserved across these three primate families, despite long periods of independent evolution. We applied connectomic electron microscopy to the specialized foveal retina where circuits for highest acuity and color vision reside. Synaptic motifs arising from the cone photoreceptor type sensitive to short (S) wavelengths and associated with "blue-yellow" (S-ON and S-OFF) color-coding circuitry were reconstructed. We found that distinctive circuitry arises from S cones for each of the three species. The S cones contacted neighboring L and M (long- and middle-wavelength sensitive) cones in humans, but such contacts were rare or absent in macaques and marmosets. We discovered a major S-OFF pathway in the human retina and established its absence in marmosets. Further, the S-ON and S-OFF chromatic pathways make excitatory-type synaptic contacts with L and M cone types in humans, but not in macaques or marmosets. Our results predict that early-stage chromatic signals are distinct in the human retina and imply that solving the human connectome at the nanoscale level of synaptic wiring will be critical for fully understanding the neural basis of human color vision.
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Affiliation(s)
- Yeon Jin Kim
- Department of Biological Structure, University of Washington, Seattle, WA98195
| | - Orin Packer
- Department of Biological Structure, University of Washington, Seattle, WA98195
| | - Andreas Pollreisz
- Department of Ophthalmology, Medical University of Vienna, Vienna1090, Austria
| | - Paul R. Martin
- Save Sight Institute and Department of Ophthalmology, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW2000, Australia
| | - Ulrike Grünert
- Save Sight Institute and Department of Ophthalmology, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW2000, Australia
| | - Dennis M. Dacey
- Department of Biological Structure, University of Washington, Seattle, WA98195
- Washington National Primate Research Center, University of Washington, Seattle, WA98195
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5
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Schottdorf M, Lee BB. A quantitative description of macaque ganglion cell responses to natural scenes: the interplay of time and space. J Physiol 2021; 599:3169-3193. [PMID: 33913164 DOI: 10.1113/jp281200] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 04/20/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Responses to natural scenes are the business of the retina. We find primate ganglion cell responses to such scenes consistent with those to simpler stimuli. A biophysical model confirmed this and predicted ganglion cell responses with close to retinal reliability. Primate ganglion cell responses to natural scenes were driven by temporal variations in colour and luminance over the receptive field centre caused by eye movements, and little influenced by interaction of centre and surround with structure in the scene. We discuss implications in the context of efficient coding of the visual environment. Much information in a higher spatiotemporal frequency band is concentrated in the magnocellular pathway. ABSTRACT Responses of visual neurons to natural scenes provide a link between classical descriptions of receptive field structure and visual perception of the natural environment. A natural scene video with a movement pattern resembling that of primate eye movements was used to evoke responses from macaque ganglion cells. Cell responses were well described through known properties of cell receptive fields. Different analyses converge to show that responses primarily derive from the temporal pattern of stimulation derived from eye movements, rather than spatial receptive field structure beyond centre size and position. This was confirmed using a model that predicted ganglion cell responses close to retinal reliability, with only a small contribution of the surround relative to the centre. We also found that the spatiotemporal spectrum of the stimulus is modified in ganglion cell responses, and this can reduce redundancy in the retinal signal. This is more pronounced in the magnocellular pathway, which is much better suited to transmit the detailed structure of natural scenes than the parvocellular pathway. Whitening is less important for chromatic channels. Taken together, this shows how a complex interplay across space, time and spectral content sculpts ganglion cell responses.
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Affiliation(s)
- Manuel Schottdorf
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, D-37077, Germany.,Max Planck Institute of Experimental Medicine, Göttingen, D-37075, Germany.,Princeton Neuroscience Institute, Princeton, NJ, 08544, USA
| | - Barry B Lee
- Graduate Center for Vision Research, Department of Biological Sciences, SUNY College of Optometry, 33 West 42nd St., New York, NY, 10036, USA.,Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, D-37077, Germany
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6
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When figure-ground segregation fails: Exploring antagonistic interactions in figure-ground perception. Atten Percept Psychophys 2020; 82:3618-3635. [PMID: 32686064 DOI: 10.3758/s13414-020-02097-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Perceptual fading of an artificial scotoma can be viewed as a failure of figure-ground segregation, providing a useful tool for investigating possible mechanisms and processes involved in figure-ground perception. Weisstein's antagonistic magnocellular/parvocellular stream figure-ground model proposes P stream activity encodes figure, and M stream activity encodes background. Where a boundary separates two regions, the region that is perceived as figure or ground is determined by the outcome of antagonism between M and P activity within each region and across the boundary between them. The region with the relatively stronger P "figure signal" is perceived as figure, and the region with the relatively stronger M "ground signal" is perceived as ground. From this perspective, fading occurs when the figure signal is overwhelmed by the ground signal. Strengthening the figure signal or weakening the ground signal should make the figure more resistant to fading. Based on research showing that red light suppresses M activity and short wavelength sensitive S-cones provide minimal input to M cells, we used red and blue light to reduce M activity in both figure and ground. The time to fade from stimulus onset until the figure completely disappeared was measured. Every combination of gray, green, red, and blue as figure and/or ground was tested. Compared with gray and green light, fade times were greatest when red or blue light either strengthened the figure signal by reducing M activity in the figure, or weakened the ground signal by reducing M activity in ground. The results support a dynamic antagonistic relationship between M and P activity contributing to figure-ground perception as envisioned in Weisstein's model.
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7
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Goddard E, Mullen KT. fMRI representational similarity analysis reveals graded preferences for chromatic and achromatic stimulus contrast across human visual cortex. Neuroimage 2020; 215:116780. [PMID: 32276074 DOI: 10.1016/j.neuroimage.2020.116780] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 03/18/2020] [Accepted: 03/24/2020] [Indexed: 01/23/2023] Open
Abstract
Human visual cortex is partitioned into different functional areas that, from lower to higher, become increasingly selective and responsive to complex feature dimensions. Here we use a Representational Similarity Analysis (RSA) of fMRI-BOLD signals to make quantitative comparisons across LGN and multiple visual areas of the low-level stimulus information encoded in the patterns of voxel responses. Our stimulus set was picked to target the four functionally distinct subcortical channels that input visual cortex from the LGN: two achromatic sinewave stimuli that favor the responses of the high-temporal magnocellular and high-spatial parvocellular pathways, respectively, and two chromatic stimuli isolating the L/M-cone opponent and S-cone opponent pathways, respectively. Each stimulus type had three spatial extents to sample both foveal and para-central visual field. With the RSA, we compare quantitatively the response specializations for individual stimuli and combinations of stimuli in each area and how these change across visual cortex. First, our results replicate the known response preferences for motion/flicker in the dorsal visual areas. In addition, we identify two distinct gradients along the ventral visual stream. In the early visual areas (V1-V3), the strongest differential representation is for the achromatic high spatial frequency stimuli, suitable for form vision, and a very weak differentiation of chromatic versus achromatic contrast. Emerging in ventral occipital areas (V4, VO1 and VO2), however, is an increasingly strong separation of the responses to chromatic versus achromatic contrast and a decline in the high spatial frequency representation. These gradients provide new insight into how visual information is transformed across the visual cortex.
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Affiliation(s)
- Erin Goddard
- McGill Vision Research, Department of Ophthalmology & Visual Sciences, McGill University, Montreal, QC, H3G1A4, Canada
| | - Kathy T Mullen
- McGill Vision Research, Department of Ophthalmology & Visual Sciences, McGill University, Montreal, QC, H3G1A4, Canada.
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8
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Thoreson WB, Dacey DM. Diverse Cell Types, Circuits, and Mechanisms for Color Vision in the Vertebrate Retina. Physiol Rev 2019; 99:1527-1573. [PMID: 31140374 PMCID: PMC6689740 DOI: 10.1152/physrev.00027.2018] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 03/27/2019] [Accepted: 04/02/2019] [Indexed: 01/13/2023] Open
Abstract
Synaptic interactions to extract information about wavelength, and thus color, begin in the vertebrate retina with three classes of light-sensitive cells: rod photoreceptors at low light levels, multiple types of cone photoreceptors that vary in spectral sensitivity, and intrinsically photosensitive ganglion cells that contain the photopigment melanopsin. When isolated from its neighbors, a photoreceptor confounds photon flux with wavelength and so by itself provides no information about color. The retina has evolved elaborate color opponent circuitry for extracting wavelength information by comparing the activities of different photoreceptor types broadly tuned to different parts of the visible spectrum. We review studies concerning the circuit mechanisms mediating opponent interactions in a range of species, from tetrachromatic fish with diverse color opponent cell types to common dichromatic mammals where cone opponency is restricted to a subset of specialized circuits. Distinct among mammals, primates have reinvented trichromatic color vision using novel strategies to incorporate evolution of an additional photopigment gene into the foveal structure and circuitry that supports high-resolution vision. Color vision is absent at scotopic light levels when only rods are active, but rods interact with cone signals to influence color perception at mesopic light levels. Recent evidence suggests melanopsin-mediated signals, which have been identified as a substrate for setting circadian rhythms, may also influence color perception. We consider circuits that may mediate these interactions. While cone opponency is a relatively simple neural computation, it has been implemented in vertebrates by diverse neural mechanisms that are not yet fully understood.
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Affiliation(s)
- Wallace B Thoreson
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center , Omaha, Nebraska ; and Department of Biological Structure, Washington National Primate Research Center, University of Washington , Seattle, Washington
| | - Dennis M Dacey
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center , Omaha, Nebraska ; and Department of Biological Structure, Washington National Primate Research Center, University of Washington , Seattle, Washington
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9
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The spatial structure of cone-opponent receptive fields in macaque retina. Vision Res 2018; 151:141-151. [DOI: 10.1016/j.visres.2017.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 05/23/2017] [Accepted: 05/30/2017] [Indexed: 11/24/2022]
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10
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Eiber C, Pietersen A, Zeater N, Solomon S, Martin P. Chromatic summation and receptive field properties of blue-on and blue-off cells in marmoset lateral geniculate nucleus. Vision Res 2018; 151:41-52. [DOI: 10.1016/j.visres.2017.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 08/04/2017] [Accepted: 09/13/2017] [Indexed: 10/18/2022]
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11
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Conway BR, Eskew RT, Martin PR, Stockman A. A tour of contemporary color vision research. Vision Res 2018; 151:2-6. [PMID: 29959956 PMCID: PMC6345392 DOI: 10.1016/j.visres.2018.06.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 06/12/2018] [Accepted: 06/23/2018] [Indexed: 11/17/2022]
Abstract
The study of color vision encompasses many disciplines, including art, biochemistry, biophysics, brain imaging, cognitive neuroscience, color preferences, colorimetry, computer modelling, design, electrophysiology, language and cognition, molecular genetics, neuroscience, physiological optics, psychophysics and physiological optics. Coupled with the elusive nature of the subjective experience of color, this wide range of disciplines makes the study of color as challenging as it is fascinating. This overview of the special issue Color: Cone Opponency and Beyond outlines the state of the science of color, and points to some of the many questions that remain to be answered in this exciting field.
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Affiliation(s)
- Bevil R Conway
- National Eye Institute and National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Rhea T Eskew
- Department of Psychology, 125 Nightingale Hall, Northeastern University, Boston, MA 02115, USA
| | - Paul R Martin
- Save Sight Institute and School of Medical Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Andrew Stockman
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, England, United Kingdom
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12
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Schmidt BP, Sabesan R, Tuten WS, Neitz J, Roorda A. Sensations from a single M-cone depend on the activity of surrounding S-cones. Sci Rep 2018; 8:8561. [PMID: 29867090 PMCID: PMC5986870 DOI: 10.1038/s41598-018-26754-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 05/18/2018] [Indexed: 11/15/2022] Open
Abstract
Color vision requires the activity of cone photoreceptors to be compared in post-receptoral circuitry. Decades of psychophysical measurements have quantified the nature of these comparative interactions on a coarse scale. How such findings generalize to a cellular scale remains unclear. To answer that question, we quantified the influence of surrounding light on the appearance of spots targeted to individual cones. The eye's aberrations were corrected with adaptive optics and retinal position was precisely tracked in real-time to compensate for natural movement. Subjects reported the color appearance of each spot. A majority of L-and M-cones consistently gave rise to the sensation of white, while a smaller group repeatedly elicited hue sensations. When blue sensations were reported they were more likely mediated by M- than L-cones. Blue sensations were elicited from M-cones against a short-wavelength light that preferentially elevated the quantal catch in surrounding S-cones, while stimulation of the same cones against a white background elicited green sensations. In one of two subjects, proximity to S-cones increased the probability of blue reports when M-cones were probed. We propose that M-cone increments excited both green and blue opponent pathways, but the relative activity of neighboring cones favored one pathway over the other.
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Affiliation(s)
- Brian P Schmidt
- Graduate Program in Neuroscience, University of Washington, Seattle, WA, 98109, USA.
- School of Optometry and Vision Science Graduate Group, University of California, Berkeley, CA, 94720, USA.
| | - Ramkumar Sabesan
- School of Optometry and Vision Science Graduate Group, University of California, Berkeley, CA, 94720, USA
- Department of Ophthalmology, University of Washington, Seattle, WA, 98109, USA
| | - William S Tuten
- School of Optometry and Vision Science Graduate Group, University of California, Berkeley, CA, 94720, USA
| | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle, WA, 98109, USA
| | - Austin Roorda
- School of Optometry and Vision Science Graduate Group, University of California, Berkeley, CA, 94720, USA
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13
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Barkan Y, Spitzer H. Neuronal Mechanism for Compensation of Longitudinal Chromatic Aberration-Derived Algorithm. Front Bioeng Biotechnol 2018; 6:12. [PMID: 29527525 PMCID: PMC5829099 DOI: 10.3389/fbioe.2018.00012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 01/23/2018] [Indexed: 11/13/2022] Open
Abstract
The human visual system faces many challenges, among them the need to overcome the imperfections of its optics, which degrade the retinal image. One of the most dominant limitations is longitudinal chromatic aberration (LCA), which causes short wavelengths (blue light) to be focused in front of the retina with consequent blurring of the retinal chromatic image. The perceived visual appearance, however, does not display such chromatic distortions. The intriguing question, therefore, is how the perceived visual appearance of a sharp and clear chromatic image is achieved despite the imperfections of the ocular optics. To address this issue, we propose a neural mechanism and computational model, based on the unique properties of the S-cone pathway. The model suggests that the visual system overcomes LCA through two known properties of the S channel: (1) omitting the contribution of the S channel from the high-spatial resolution pathway (utilizing only the L and M channels). (b) Having large and coextensive receptive fields that correspond to the small bistratified cells. Here, we use computational simulations of our model on real images to show how integrating these two basic principles can provide a significant compensation for LCA. Further support for the proposed neuronal mechanism is given by the ability of the model to predict an enigmatic visual phenomenon of large color shifts as part of the assimilation effect.
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Affiliation(s)
- Yuval Barkan
- Biomedical Engineering Department, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Hedva Spitzer
- Electrical Engineering School, Faculty of Engineering, Tel-Aviv University, Tel-Aviv, Israel
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14
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Le Floch A, Ropars G. Left-right asymmetry of the Maxwell spot centroids in adults without and with dyslexia. Proc Biol Sci 2017; 284:20171380. [PMID: 29046375 PMCID: PMC5666095 DOI: 10.1098/rspb.2017.1380] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/22/2017] [Indexed: 12/12/2022] Open
Abstract
In human vision, the brain has to select one view of the world from our two eyes. However, the existence of a clear anatomical asymmetry providing an initial imbalance for normal neural development is still not understood. Using a so-called foveascope, we found that for a cohort of 30 normal adults, the two blue cone-free areas at the centre of the foveas are asymmetrical. The noise-stimulated afterimage dominant eye introduced here corresponds to the circular blue cone-free area, while the non-dominant eye corresponds to the diffuse and irregular elliptical outline. By contrast, we found that this asymmetry is absent or frustrated in a similar cohort of 30 adults with normal ocular status, but with dyslexia, i.e. with visual and phonological deficits. In this case, our results show that the two Maxwell centroid outlines are both circular but lead to an undetermined afterimage dominance with a coexistence of primary and mirror images. The interplay between the lack of asymmetry and the development in the neural maturation of the brain pathways suggests new implications in both fundamental and biomedical sciences.
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Affiliation(s)
- Albert Le Floch
- Laboratoire de Physique des Lasers, UFR SPM, Université de Rennes 1, 35042 Rennes, France
- Laboratoire d'Electronique Quantique et Chiralités, 20 Square Marcel Bouget, 35700 Rennes, France
- Université Bretagne Loire, 35044 Rennes, France
| | - Guy Ropars
- Laboratoire de Physique des Lasers, UFR SPM, Université de Rennes 1, 35042 Rennes, France
- Université Bretagne Loire, 35044 Rennes, France
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15
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Schmidt BP, Touch P, Neitz M, Neitz J. Circuitry to explain how the relative number of L and M cones shapes color experience. J Vis 2017; 16:18. [PMID: 27366885 PMCID: PMC4927209 DOI: 10.1167/16.8.18] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The wavelength of light that appears unique yellow is surprisingly consistent across people even though the ratio of middle (M) to long (L) wavelength sensitive cones is strikingly variable. This observation has been explained by normalization to the mean spectral distribution of our shared environment. Our purpose was to reconcile the nearly perfect alignment of everyone's unique yellow through a normalization process with the striking variability in unique green, which varies by as much as 60 nm between individuals. The spectral location of unique green was measured in a group of volunteers whose cone ratios were estimated with a technique that combined genetics and flicker photometric electroretinograms. In contrast to unique yellow, unique green was highly dependent upon relative cone numerosity. We hypothesized that the difference in neural architecture of the blue-yellow and red-green opponent systems in the presence of a normalization process creates the surprising dependence of unique green on cone ratio. We then compared the predictions of different theories of color vision processing that incorporate L and M cone ratio and a normalization process. The results of this analysis reveal that—contrary to prevailing notions--postretinal contributions may not be required to explain the phenomena of unique hues.
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16
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Majander A, João C, Rider AT, Henning GB, Votruba M, Moore AT, Yu-Wai-Man P, Stockman A. The Pattern of Retinal Ganglion Cell Loss in OPA1-Related Autosomal Dominant Optic Atrophy Inferred From Temporal, Spatial, and Chromatic Sensitivity Losses. Invest Ophthalmol Vis Sci 2017; 58:502-516. [PMID: 28125838 PMCID: PMC5283089 DOI: 10.1167/iovs.16-20309] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Progressive retinal ganglion cell (RGC) loss is the pathological hallmark of autosomal dominant optic atrophy (DOA) caused by pathogenic OPA1 mutations. The aim of this study was to conduct an in-depth psychophysical study of the visual losses in DOA and to infer any selective vulnerability of visual pathways subserved by different RGC subtypes. Methods We recruited 25 patients carrying pathogenic OPA1 mutations and age-matched healthy individuals. Spatial contrast sensitivity functions (SCSFs) and chromatic contrast sensitivity were quantified, the latter using the Cambridge Colour Test. In 11 patients, long (L) and short (S) wavelength-sensitive cone temporal acuities were measured as a function of target illuminance, and L-cone temporal contrast sensitivity (TCSF) as a function of temporal frequency. Results Spatial contrast sensitivity functions were abnormal, with the loss of sensitivity increasing with spatial frequency. Further, the highest L-cone temporal acuity fell on average by 10 Hz and the TCSFs by 0.66 log10 unit. Chromatic thresholds along the protan, deutan, and tritan axes were 8, 9, and 14 times higher than normal, respectively, with losses increasing with age and S-cone temporal acuity showing the most significant age-related decline. Conclusions Losses of midget parvocellular, parasol magnocellular, and bistratified koniocellular RGCs could account for the losses of high spatial frequency sensitivity and protan and deutan sensitivities, high temporal frequency sensitivity, and S-cone temporal and tritan sensitivities, respectively. The S-cone-related losses showed a significant deterioration with increasing patient age and could therefore prove useful biomarkers of disease progression in DOA.
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Affiliation(s)
- Anna Majander
- University College London, Institute of Ophthalmology, London, United Kingdom 2Moorfields Eye Hospital, London, United Kingdom 3Department of Ophthalmology, University of Helsinki, and Helsinki University Hospital, Helsinki, Finland
| | - Catarina João
- University College London, Institute of Ophthalmology, London, United Kingdom
| | - Andrew T Rider
- University College London, Institute of Ophthalmology, London, United Kingdom
| | - G Bruce Henning
- University College London, Institute of Ophthalmology, London, United Kingdom
| | - Marcela Votruba
- School of Optometry and Vision Sciences, Cardiff University Cardiff, and Cardiff Eye Unit, University Hospital Wales, Cardiff, United Kingdom
| | - Anthony T Moore
- University College London, Institute of Ophthalmology, London, United Kingdom 2Moorfields Eye Hospital, London, United Kingdom 5Ophthalmology Department, University of California-San Francisco School of Medicine, San Francisco, California, United States
| | - Patrick Yu-Wai-Man
- University College London, Institute of Ophthalmology, London, United Kingdom 2Moorfields Eye Hospital, London, United Kingdom 6Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University and Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Andrew Stockman
- University College London, Institute of Ophthalmology, London, United Kingdom
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D'Souza DV, Auer T, Frahm J, Strasburger H, Lee BB. Dependence of chromatic responses in V1 on visual field eccentricity and spatial frequency: an fMRI study. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2016; 33:A53-A64. [PMID: 26974942 DOI: 10.1364/josaa.33.000a53] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Psychophysical sensitivity to red-green chromatic modulation decreases with visual eccentricity, compared to sensitivity to luminance modulation, even after appropriate stimulus scaling. This is likely to occur at a central, rather than a retinal, site. Blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) responses to stimuli designed to separately stimulate different afferent channels' [red-green, luminance, and short-wavelength (S)-cone] circular gratings were recorded as a function of visual eccentricity (±10 deg) and spatial frequency (SF) in human primary visual cortex (V1) and further visual areas (V2v, V3v). In V1, the SF tuning of BOLD fMRI responses became coarser with eccentricity. For red-green and luminance gratings, similar SF tuning curves were found at all eccentricities. The pattern for S-cone modulation differed, with SF tuning changing more slowly with eccentricity than for the other two modalities. This may be due to the different retinal distribution with eccentricity of this receptor type. A similar pattern held in V2v and V3v. This would suggest that transformation or spatial filtering of the chromatic (red-green) signal occurs beyond these areas.
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Novales Flamarique I, Wachowiak M. Functional segregation of retinal ganglion cell projections to the optic tectum of rainbow trout. J Neurophysiol 2015; 114:2703-17. [PMID: 26334009 DOI: 10.1152/jn.00440.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 09/01/2015] [Indexed: 11/22/2022] Open
Abstract
The interpretation of visual information relies on precise maps of retinal representation in the brain coupled with local circuitry that encodes specific features of the visual scenery. In nonmammalian vertebrates, the main target of ganglion cell projections is the optic tectum. Although the topography of retinotectal projections has been documented for several species, the spatiotemporal patterns of activity and how these depend on background adaptation have not been explored. In this study, we used a combination of electrical and optical recordings to reveal a retinotectal map of ganglion cell projections to the optic tectum of rainbow trout and characterized the spatial and chromatic distribution of ganglion cell fibers coding for increments (ON) and decrements (OFF) of light. Recordings of optic nerve activity under various adapting light backgrounds, which isolated the input of different cone mechanisms, yielded dynamic patterns of ON and OFF input characterized by segregation of these two fiber types. Chromatic adaptation decreased the sensitivity and response latency of affected cone mechanisms, revealing their variable contributions to the ON and OFF responses. Our experiments further demonstrated restricted input from a UV cone mechanism to the anterolateral optic tectum, in accordance with the limited presence of UV cones in the dorsotemporal retina of juvenile rainbow trout. Together, our findings show that retinal inputs to the optic tectum of this species are not homogeneous, exhibit highly dynamic activity patterns, and are likely determined by a combination of biased projections and specific retinal cell distributions and their activity states.
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Affiliation(s)
- Iñigo Novales Flamarique
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada; Department of Biology, University of Victoria, Victoria, British Columbia, Canada; and Marine Biological Laboratory, Woods Hole, Massachusetts
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Spitschan M, Aguirre GK, Brainard DH. Selective stimulation of penumbral cones reveals perception in the shadow of retinal blood vessels. PLoS One 2015; 10:e0124328. [PMID: 25897842 PMCID: PMC4405364 DOI: 10.1371/journal.pone.0124328] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/03/2015] [Indexed: 12/13/2022] Open
Abstract
In 1819, Johann Purkinje described how a moving light source that displaces the shadow of the retinal blood vessels to adjacent cones can produce the entopic percept of a branching tree. Here, we describe a novel method for producing a similar percept. We used a device that mixes 56 narrowband primaries under computer control, in conjunction with the method of silent substitution, to present observers with a spectral modulation that selectively targeted penumbral cones in the shadow of the retinal blood vessels. Such a modulation elicits a clear Purkinje-tree percept. We show that the percept is specific to penumbral L and M cone stimulation and is not produced by selective penumbral S cone stimulation. The Purkinje-tree percept was strongest at 16 Hz and fell off at lower (8 Hz) and higher (32 Hz) temporal frequencies. Selective stimulation of open-field cones that are not in shadow, with penumbral cones silenced, also produced the percept, but it was not seen when penumbral and open-field cones were modulated together. This indicates the need for spatial contrast between penumbral and open-field cones to create the Purkinje-tree percept. Our observation provides a new means for studying the response of retinally stabilized images and demonstrates that penumbral cones can support spatial vision. Further, the result illustrates a way in which silent substitution techniques can fail to be silent. We show that inadvertent penumbral cone stimulation can accompany melanopsin-directed modulations that are designed only to silence open-field cones. This in turn can result in visual responses that might be mistaken as melanopsin-driven.
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Affiliation(s)
- Manuel Spitschan
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Geoffrey K. Aguirre
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (DB); (GA)
| | - David H. Brainard
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (DB); (GA)
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Abstract
We review the features of the S-cone system that appeal to the psychophysicist and summarize the celebrated characteristics of S-cone mediated vision. Two factors are emphasized: First, the fine stimulus control that is required to isolate putative visual mechanisms and second, the relationship between physiological data and psychophysical approaches. We review convergent findings from physiology and psychophysics with respect to asymmetries in the retinal wiring of S-ON and S-OFF visual pathways, and the associated treatment of increments and decrements in the S-cone system. Beyond the retina, we consider the lack of S-cone projections to superior colliculus and the use of S-cone stimuli in experimental psychology, for example to address questions about the mechanisms of visually driven attention. Careful selection of stimulus parameters enables psychophysicists to produce entirely reversible, temporary, "lesions," and to assess behavior in the absence of specific neural subsystems.
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Horwitz GD. What studies of macaque monkeys have told us about human color vision. Neuroscience 2014; 296:110-5. [PMID: 25445192 DOI: 10.1016/j.neuroscience.2014.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 09/29/2014] [Accepted: 10/01/2014] [Indexed: 11/29/2022]
Abstract
Animal models are a necessary component of systems neuroscience research. Determining which animal model to use for a given study involves a complicated calculus. Some experimental manipulations are easily made in some animal models but impossible in others. Some animal models are similar to humans with respect to particular scientific questions, and others are less so. In this review, I discuss work done in my laboratory to investigate the neural mechanisms of color vision in the rhesus macaque. The emphasis is on the strengths of the macaque model, but shortcomings are also discussed.
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Affiliation(s)
- G D Horwitz
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States; Washington National Primate Research Center, Seattle, WA, United States.
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Handa RJ, McGivern RF. Steroid Hormones, Receptors, and Perceptual and Cognitive Sex Differences in the Visual System. Curr Eye Res 2014; 40:110-27. [DOI: 10.3109/02713683.2014.952826] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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