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Publications (266)
Color vision is a perceptual capacity present in animals whose nervous systems are so organized that they can encode and evaluate variations in the spectral distributions of light reaching their eyes. In vertebrates, the group forming the focus of this article, color vision, like all aspects of daylight vision, is initiated by the absorption of lig...
Early color-matching studies established that normal human color vision is trichromatic. Subsequent research revealed a causal link between trichromacy and the presence in the retina of three classes of cone photopigments. Over the years, measurements of the photopigment complements of other species have expanded greatly and these are frequently us...
Color vision is a perceptual capacity that allows animals to discriminate between visual targets that differ consistently only in wavelength content. So defined, a majority of all vertebrates possess some color vision. Since about 1990, research on primate color vision has been directed toward documenting the nature of color vision across different...
Abstract: Research conducted in recent years has documented the widespread
presence of various forms of color vision in species from across the animal kingdom,
helped to develop an understanding of the basic biological mechanisms that
underlie this sensory capacity, and provided some insights into the utility of color
vision in the natural world. T...
We perceive color everywhere and on everything that we encounter in daily life. Color science has progressed to the point where a great deal is known about the mechanics, evolution, and development of color vision, but less is known about the relation between color vision and psychology. However, color psychology is now a burgeoning, exciting area...
Vision provides the most important source of information about our ever-changing world. Scientists and philosophers have long sought to understand how we are able to accomplish effortlessly what seems nearly miraculous--the conversion of light into sight. For many years the author participated in a research program directed toward understanding the...
The two principal theories of color vision that emerged in the nineteenth century offered alternative ideas about the nature of the biological mechanisms that underlie the percepts of color. One, the Young-Helmholtz theory, proposed that the visual system contained three component mechanisms whose individual activations were linked to the perceptio...
All mammalian cone photopigments are derived from the operation of representatives from two opsin gene families (SWS1 and LWS in marsupial and eutherian mammals; SWS2 and LWS in monotremes), a process that produces cone pigments with respective peak sensitivities in the short and middle-to-long wavelengths. With the exception of a number of primate...
Almost all animals have eyes and make extensive use of visual information to support the critical choices they must make to survive and prosper. The chapter starts with a discussion of the informational possibilities offered by the photic environment and then provides a comparative examination of the basic biological mechanisms underlying animal vi...
Color vision is conventionally defined as the ability of animals to reliably discriminate among objects and lights based solely on differences in their spectral properties. Although the nature of color vision varies widely in different animals, a large majority of all vertebrate species possess some color vision and that fact attests to the adaptiv...
The selective advantages to primates of trichromatic color vision, allowing discrimination among the colors green, yellow, orange, and red, remain poorly understood. We test the hypothesis that, for primates, an advantage of trichromacy over dichromacy, in which such colors are apt to be confused, lies in the detection of yellow, orange, or red (YO...
The retinas of harbor seals (Phoca vitulina) contain two morphologically distinct photoreceptor types: rods and cones. The spectral properties of the cones have not been previously studied. The spectral sensitivities of the cones of harbor seals were measured using a retinal gross potential technique, flicker photometric electroretinography. We fou...
The color vision of most platyrrhine primates is determined by alleles at the polymorphic X-linked locus coding for the opsin responsible for the middle- to long-wavelength (M/L) cone photopigment. Females who are heterozygous at the locus have trichromatic vision, whereas homozygous females and all males are dichromatic. This study characterized t...
Color vision has captivated the interest of innumerable people, both amateurs and visual scientists, in the three hundred years since Newton reported his “New Theory about Light and Colours” to the Royal Society. Thousands of psychophysical experiments studying the effects of numerous variables on human color perception have provided us with a rich...
The functional impacts and genetic bases of the human photopigment polymorphisms have been intensively studied and debated. Even though they attract much attention, photopigment polymorphisms that cause significant changes in color vision are relatively infrequent in humans and effectively absent in other catarrhine primates. By contrast, photopigm...
Thirty years ago virtually everything known about primate color vision derived from psychophysical studies of normal and color-defective humans and from physiological investigations of the visual system of the macaque monkey, that most popular of human surrogates for this purpose. The years since have witnessed much progress toward the goal of unde...
There have been significant advances in our understanding of mammalian color vision over the past 15 years. This paper reviews a number of topics that have been central to these recent efforts, including: (1) the extent and nature of ultraviolet vision in mammals, (2) the evolutionary loss of short-wavelength-sensitive cones in some mammals, (3) th...
Only two of the four cone opsin gene families found in vertebrates are represented in contemporary eutherian and marsupial species. Recent genetic studies of two species of South American marsupial detected the presence of representatives from two of the classes of cone opsin genes and the structures of these genes predicted cone pigments with resp...
Mammalian photopigments are typically located within the lipid membranes of rod and cone photoreceptors. They absorb incident light and, through a complex phototransduction cascade, relay information to downstream visual neurons. Recent results emerging from a variety of experimental approaches have greatly enhanced our understanding of photopigmen...
This chapter describes a study of photopigment polymorphism in prosimians. A noninvasive electrophysiological technique, electroretinogram (ERG) flicker photometry was used to measure spectral sensitivity in three adult (one male, two female) black and white ruffed lemurs (Varecia variegata variegata). The pigment polymorphism observed in black and...
Colour vision allows animals to reliably distinguish differences in the distributions of spectral energies reaching the eye. Although not universal, a capacity for colour vision is sufficiently widespread across the animal kingdom to provide prima facie evidence of its importance as a tool for analysing and interpreting the visual environment. The...
Analyses of primate visual pigments show that our color vision evolved in an unusual way and that the brain is more adaptable than generally thought
Thirty years ago virtually everything known about primate color vision derived from psychophysical studies of normal and color-defective humans and from physiological investigations of the visual system of the macaque monkey, the most popular of human surrogates for this purpose. The years since have witnessed much progress toward the goal of under...
Although the idea clearly has a long history, the nineteenth-century English naturalist John Lubbock was among the first to
provide a compelling experimental demonstration that the visual worlds of other animals can be distinctly different from those
experienced by humans. Over the years since that time, an immense body of literature has been accum...
Studies of Syrian golden hamsters (Mesocricetus auratus) have yielded contradictory evidence as to whether the retina of this species supports a population of cones containing short-wavelength sensitive pigments. We undertook a re-examination of this issue by (a) measuring lens transmission, (b) determining complete spectral sensitivity functions u...
The dendritic patterning of retinal horizontal cells has been shown to be specified by the cone photoreceptor afferents. The present investigation has addressed whether this specification is due to visually dependent synaptic transmission in the outer plexiform layer or to some other early, pre-visual, neural activity. Individually labeled horizont...
The mouse retina contains two classes of cone photopigment with respective peak sensitivities in the middle (M) wavelengths and in the ultraviolet (UV) portion of the spectrum. To examine the functional roles subserved by the UV pigment, the absorption of light by the mouse lens was measured and voltage versus intensity (V-log I) functions were der...
Makous suggests that the novel color vision documented in knock-in mice neither requires visual system plasticity nor implies the emergence of a new dimension of sensory experience. We explain why we disagree.
The visual worlds of most primates are rich with potential color signals, and many representatives of the order have evolved
the biological mechanisms that allow them to exploit these sources of information. Unlike the catarrhines, platyrrhines typically
have sex-linked polymorphic color vision that provides individuals with any of several distinct...
People often experience age-related declines in cone-based visual capacities despite an absence of apparent visual pathology. Although mice are used as models of human visual pathologies associated with aging, little is known about how age impacts vision in animals with disease-free retinas since most studies have heretofore examined relatively you...
Aotus is a platyrrhine primate that has been classically considered to be nocturnal. Earlier research revealed that this animal lacks a color vision capacity because, unlike all other platyrrhine monkeys, Aotus has a defect in the opsin gene that is required to produce short-wavelength sensitive (S) cone photopigment. Consequently, Aotus retains on...
Changes in the genes encoding sensory receptor proteins are an essential step in the evolution of new sensory capacities. In primates, trichromatic color vision evolved after changes in X chromosome-linked photopigment genes. To model this process, we studied knock-in mice that expressed a human long-wavelength-sensitive (L) cone photopigment in th...
X-linked photopigment polymorphism produces six different color vision phenotypes in most species of New World monkey. In the subfamily Callitrichinae, the three M/L alleles underlying these different phenotypes are present at unequal frequencies suggesting that selective pressures other than heterozygous-advantage operate on these alleles. Earlier...
Rod and cone visual pigments of 11 marine carnivores were evaluated. Rod, middle/long-wavelength sensitive (M/L) cone, and short-wavelength sensitive (S) cone opsin (if present) sequences were obtained from retinal mRNA. Spectral sensitivity was inferred through evaluation of known spectral tuning residues. The rod pigments of all but one of the pi...
Platyrrhine monkeys typically have only a single X-chromosome opsin gene. Alleles of this gene code for multiple versions of middle- to long-wavelength cone photopigments. X-chromosome inactivation provides heterozygous females with a retinal mosaic of cones containing either of two types of M and L pigment, thus establishing the photopigment basis...
Introduction: sampling and retinal specializationSpatial sampling: signals, noise and image statisticsColorNocturnality and the origins of primate visionReferences
IntroductionStructure of visual pigmentsVisual pigment genes in primatesOrigin of duplication in Old World primatesL and M gene variation in Old World primatesColor vision in platyrrhines and prosimiansEvolution of trichromacySummary and conclusionsReferences
Transgenic coneless mice were initially developed to study retinal function in the absence of cones. In coneless mice created by expressing an attenuated diphtheria toxin under the control of flanking sequences from the human L-cone opsin gene, a small number of cones (3-5% of the normal complement) survive in a retina that otherwise appears struct...
Most New World (platyrrhine) monkeys have M/L cone photopigment polymorphisms that map directly into individual variations in visual sensitivity and color vision. We used electroretinogram flicker photometry to examine M/L cone photopigments in the New World monkey Callicebus moloch (the dusky Titi). Like other New World monkeys, this species has a...
Among mammals, only the primates have acquired the biological machinery needed for highly acute color vision. That distinction led Gordon Walls, perhaps the foremost authority on comparative vision of this century, to suggest long ago that “the color vision of the higher primates is assuredly a law unto itself, genetically and historically speaking...
Pocket gophers (Thomomys bottae) are rodents that spend much of their lives in near-lightless subterranean burrows. The visual adaptations associated with this extreme environment were investigated by making anatomical observations of retinal organization and by recording retinal responses to photic stimulation. The size of the eye is within the no...
Flicker electroretinography (ERG) was used to examine the in situ photopic (cone-photoreceptor based) spectral sensitivities of Green and Loggerhead Sea Turtles. Both species were responsive to wavelengths from 440–700 nm, and both had peak sensitivity in the long wavelength portion of the spectrum (∼580 nm). For Loggerhead Sea Turtles, no measurab...
Recent years have witnessed a growing interest in learning how colour vision has evolved. This trend has been fuelled by an enhanced understanding of the nature and extent of colour vision among contemporary species, by a deeper understanding of the paleontological record and by the application of new tools from molecular biology. This review provi...
Most platyrrhine monkeys have a triallelic M/L opsin gene polymorphisin that underlies significant individual variations in color vision. A survey of the frequencies of these polymorphic genes Suggests that the three alleles occur with equal frequency among squirrel monkeys (subfamily Cebinae), but are not equally frequent in a number of species fr...
Most platyrrhine monkeys have a triallelic M/L opsin gene polymorphism that underlies significant individual variations in color vision. A survey of the frequencies of these polymorphic genes suggests that the three alleles occur with equal frequency among squirrel monkeys (subfamily Cebinae), but are not equally frequent in a number of species fro...
The mouse retina contains both middle-wavelength-sensitive (M) and ultraviolet-sensitive (UV) photopigments that are coexpressed in cones. To examine some potential visual consequences of cone pigment coexpression, spectral sensitivity functions were measured in mice (Mus musculus) using both the flicker electroretinogram (ERG) and behavioral discr...
Photopigments serve as essential gatekeepers in that they regulate which features of the photic environment get translated
into neural signals in the visual system and thus can potentially contribute to sight. Over the past 20 years considerable
progress has been made in understanding these remarkable molecules and elucidating their roles in vision...
An essential reference book for visual science. Visual science is the model system for neuroscience, its findings relevant to all other areas. This massive collection of papers by leading researchers in the field will become an essential reference for researchers and students in visual neuroscience, and will be of importance to researchers and prof...
Among eutherian mammals, only primates possess trichromatic color vision. In Old World primates, trichromacy was made possible by a visual pigment gene duplication. In most New World primates, trichromacy is based on polymorphic variation in a single X-linked gene that produces, by random X inactivation, a patchy mosaic of spectrally distinct cone...
Trichromatic color vision is routine among catarrhine primates, but occurs only as a variant form of color vision in some individuals in most platyrrhine genera. This arises from a fundamental difference in the organization of X-chromosome cone opsin genes in these two lineages: catarrhines have two opsin genes specifying middle- and long-wavelengt...
The degu (Octodon degus) is a diurnal rodent, native to Chile. Basic features of vision and visual organization in this species were examined in a series of anatomical, electrophysiological and behavioral experiments. The lens of the degu eye selectively absorbs short-wavelength light and shows a progressive increase in optical density as a functio...
The topic of colour vision is one that integrates research from psychology, neuroscience, biology, ophthalmology, physics, and genetics. How do we make sense of colour in the world, and how has such an ability evolved in humans? How are colours discriminated by the retina, and how does the brain interpret chromatic information? How can our genes in...
Light provides a very rich source of information that many animals can use in the guidance and control behavior. Considerable progress has been made in understanding how this comes about through the comparison of visual capacities and visual biology across widely variant species. This chapter summarizes that progress by first considering some basic...
Previous research revealed significant individual variations in opsin genes and cone photopigments in several species of platyrrhine (New World) monkeys and showed that these in turn can yield significant variations in color vision. To extend the understanding of the nature of color vision in New World monkeys, electroretinogram flicker photometry...
Previous research revealed significant individual variations in opsin genes and cone photopigments in several species of platyr-rhine (New World) monkeys and showed that these in turn can yield significant variations in color vision. To extend the understanding of the nature of color vision in New World monkeys, electroretinogram flicker photometry...
To compare the morphologic and functional recovery of the retina after detachment and reattachment in an animal with a cone-dominant retina, the ground squirrel.
Ground squirrel (Spermophilus beecheyi) retinas were detached for 1 day and reattached for 7, 35, or 96 days (n = 2, each time point). Flicker ERGs were recorded 1 day after the detachment...
The spatial distributions of photoreceptors and retinal ganglion cells were examined in the spotted hyena (Crocuta crocuta). Two populations of cones were identified by immunocytochemical labeling. The hyena retina contains approximately 2.3 million middle- to long-wavelength sensitive (M/L) cones that reach peak densities of about 7,500/mm(2) in t...
Color vision requires the presence in the retina of multiple types of cone photopigment and appropriate nervous-system connections. In recent years, the structures of genes specifying photopigment opsins have come under increasing scrutiny. In many animal groups (e.g., fish, reptiles, and birds), representatives of four separate cone opsin gene fam...
The spectral mechanisms of the ferret (Mustela putorious furo) were studied with electroretinogram (ERG) flicker photometry. Variations in adaptation state and flicker rate were used to define corneally based spectral sensitivities for the three classes of receptor present in the retina of this mustelid-rods (lambdamax = 505 nm), S cones (430 nm),...
Unique yellow is considered to represent the equilibrium point of the red-green opponent chromatic mechanism. There are several hypotheses that attempt to explain how this equilibrium point is established. The determinant for unique yellow, however, has not yet been clarified. Here we explored whether the L/M cone ratio or visual information determ...
In people, retinal detachment often leads to a significant loss in cone-based vision. Most of the animal models commonly used for studying the consequences of retinal detachment have rod-dominated retinas. The purpose of this investigation was to evaluate the possibility that the ground squirrel, a rodent with a heavily cone-dominated retina, might...
A recent genetic investigation found some species of prosimian to have an opsin gene polymorphism [Nature 402 (1999) 36]. In the present study the functional implications of this finding were explored in a correlated investigation of opsin genes and spectral sensitivity measurements of a diurnal prosimian, Coquerel's sifaka (Propithecus verreauxi c...
this paper we examine the functional consequences of variation in the L/M cone ratio for two individuals whose ratios were studied by direct imaging. The L/M cone ratio for the two observers was quite different. A genetic analysis was used to determine L and M cone spectra appropriate for each observer. Rayleigh matches confirmed the use of these c...
this article, we examine flicker ERG responses to stimuli that modulate individual cone classes in various ratios. This allows us to study how signals from different cone classes combine to generate the overall electrical response. We used a novel flicker-photometric paradigm. In this technique, the responses to various test modulations are balance...
Rats (Rattus norvegicus) have two classes of cone, one containing an ultraviolet (UV)-sensitive photopigment and the other housing a pigment maximally sensitive in the middle (M) wavelengths of the visible spectrum. The manner in which signals from these two cone types contribute to rat vision was investigated through recordings of a gross electric...
Most New World monkeys have an X-chromosome opsin gene polymorphism that produces a variety of different colour vision phenotypes. Howler monkeys (Alouatta), one of the four genera in the family Atelidae lack this polymorphism. Instead, they have acquired uniform trichromatic colour vision similar to that of Old World monkeys, apes and people throu...
In an article published in the inaugural volume of this journal, Tigges [1]reported results from tests of an orang-utan (Pongo pygmaeus) and three gibbons (Hylobates lar) that were trained to discriminate colored papers from among a series of gray papers that varied widely in reflectance. Although the orang-utan learned to discriminate successfully...
This article examines the question of whether the congenital red/green color vision defects that are common in human populations can be detected in other catarrhine primates. Spectral sensitivity functions obtained from more than 100 Old World monkeys and apes reveal no hint of such individual variation. A literature survey on the subject leads to...
© 2000 Optical Society of America
Direct imaging of the retina by adaptive optics allows assessment of the relative number of long-wavelength-sensitive (L) and middle-wavelength-sensitive (M) cones in living human eyes. We examine the functional consequences of variation in the relative numbers of L and M cones (L/M cone ratio) for two observers whose ratios were measured by direct...
To develop methods for recording human electroretinogram (ERG) responses to stimuli that modulate different classes of cones in various ratios, to draw inferences about the combination of cone signal in early retinal processing.
Subjects viewed large-field temporal modulations presented on a computer-controlled color monitor. A flicker photometric...
It is often assumed that all Old World monkeys share the same trichromatic colour vision, but the evidence in support of this conclusion is sparse as only a small fraction of all Old World monkey species have been tested. To address this issue, spectral sensitivity functions were measured in animals from eight species of Old World monkey (five cerc...
Macaque monkeys are widely used as a model species for investigations of the biology of human vision. Previous measurements suggest that the cone-based spectral sensitivity of these two primates is greatly similar, but perhaps not identical. We measured the photopic spectral sensitivity of 42 male macaque monkeys from two species (Macaca mulatta, M...
Polymorphic color vision is characteristic of many species of New World monkey. A fundamental feature of the polymorphism is that male monkeys are routinely dichromatic. A recent paper describes an experiment in which Cebus monkeys were required to discriminate between pairs of Munsell color chips (Pessoa VF, Tavares MCH, Aguiar L, Gomes UR, Tomaz...
Genetically driven alterations in the complement of retinal photopigments are fundamental steps in the evolution of vision. We sought to determine how a newly added photopigment might impact vision by studying a transgenic mouse that expresses a human cone photopigment. Electroretinogram (ERG) measurements indicate that the added pigment works well...
The mosaic of photoreceptors is regarded as a prime example of the precise control of cellular positioning in the vertebrate nervous system. This study was undertaken with the idea that understanding the intrinsic geometrical features of photoreceptor mosaics is a necessary step to unveil the biological mechanisms governing their formation. We show...
Results from earlier experiments indicate that different species of rodent vary both in the number of cone types found in their retinas and in the spectral sensitivities of the cone pigments. These features have now been examined in two types of hamster commonly used for research purposes: Syrian golden hamsters (Mesocricetus auratus) and Siberian...
Descriptions of living primates inevitably include an acknowledgement of the overwhelming importance of sight for primate behavior, and they usually identify as unique primate characteristics a number of features of the visual system. These features include frontally-directed eyes and large binocular fields, a high concentration of ganglion cells i...
Studies carried out over the past two decades show that many platyrrhine (New World) monkeys have polymorphic color vision. This condition results from the sorting of allelic versions of X-chromosome cone opsin genes at a single gene site, yielding a mixture of dichromatic and trichromatic phenotypes in the population. Two genera of platyrrhine mon...
Changes in retinal photopigments represent a fundamental step in the evolution of visual systems, in that addition of new pigment types or alterations in the spectral absorption properties of existing pigments modify visual capacities and thus open new visual worlds. To provide a tool that would allow direct examination of the changes caused by the...
The distributions of rod and cone photoreceptors have been determined in the retina of the California ground squirrel, Spermophilus beecheyi. Retinas were fixed by perfusion and the rods and cones were detected with indirect immunofluorescence using opsin antibodies. Local densities were determined at 2-mm intervals across the entire retina, from w...
Electroretinogram (ERG) flicker photometry was used to measure the spectral properties of cones in three common ungulates-cattle (Bos taurus), goats (Capra hircus), and sheep (Ovis aries). Two cone mechanisms were identified in each species. The location of peak sensitivity of an S-cone mechanism varied from about 444 to 455 nm for the three specie...
The retinas of harbor seals (Phoca vitulina) contain two morphologically distinct photoreceptor types: rods and cones. The spectral properties of the cones have not been previously studied. The spectral sensitivities of the cones of harbor seals were measured using a retinal gross potential technique, flicker photometric electroretinography. We fou...
The spectral sensitivity of the common chimpanzee (Pan troglodytes) was measured with electroretinogram (ERG) flicker photometry. Chromatic adaptation conditions were used to establish the presence of S-, M- and L-cone pigments. Each of 26 chimpanzees showed substantial and approximately equivalent adaptational changes over the middle and long wave...
