Modeling chromatic contrast detectors in the primate visual system

1991 ◽  
pp. 361-373
Author(s):  
Peter Gouras
Keyword(s):  
Visual System ◽  
Chromatic Contrast

The influence of stimulus and background colour on signal visibility in the lizard Anolis cristatellus

2001 ◽  
Vol 204 (9) ◽  
pp. 1559-1575 ◽  
Author(s):  
L.J. Fleishman ◽  
M. Persons
Keyword(s):  
Visual System ◽  
Brightness Contrast ◽  
System Response ◽  
Signal Design ◽  
Light Conditions ◽  
Chromatic Contrast ◽  
Long Wavelength ◽  
Peak Sensitivity ◽  
Multi Linear Regression ◽  
To Receive

Anoline lizards communicate with visual displays in which they open and close a colourful throat fan called the dewlap. We used a visual fixation reflex as an assay to test the effects of stimulus versus background chromatic and brightness contrast on the probability of detecting a moving coloured (i.e. dewlap-like) stimulus in Anolis cristatellus. The probability of stimulus detection depended on two additive visual-system channels, one responding to brightness contrast and one responding to chromatic contrast, independent of brightness. The brightness channel was influenced only by wavelengths longer than 450nm and probably received input only from middle- and/or long-wavelength photoreceptors. The chromatic contrast channel appeared to receive input from three, or possibly four, different classes of cone in the anoline retina, including one with peak sensitivity in the ultraviolet. We developed a multi-linear regression equation that described most of the results of this study to a reasonable degree of accuracy. In the future, this equation could be used to predict the relative visibility of different-coloured stimuli in different habitat light conditions, which should be very useful for testing hypotheses that attempt to relate habitat light conditions and visual-system response to the evolution of signal design.

scholarly journals A detailed investigation of the visual system and visual ecology of the Barrier Reef anemonefish, Amphiprion akindynos

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sara M. Stieb ◽  
Fanny de Busserolles ◽  
Karen L. Carleton ◽  
Fabio Cortesi ◽  
Wen-Sung Chung ◽  
...  
Keyword(s):  
Visual System ◽  
Multidisciplinary Approach ◽  
Barrier Reef ◽  
Chromatic Contrast ◽  
Sequential Hermaphroditism ◽  
Single Cone ◽  
Host Anemone ◽  
Colour Patterns ◽  
Cone Opsins ◽  
Species Ecology

Abstract Vision plays a major role in the life of most teleosts, and is assumingly well adapted to each species ecology and behaviour. Using a multidisciplinary approach, we scrutinised several aspects of the visual system and ecology of the Great Barrier Reef anemonefish, Amphiprion akindynos, including its orange with white patterning, retinal anatomy and molecular biology, its symbiosis with anemones and sequential hermaphroditism. Amphiprion akindynos possesses spectrally distinct visual pigments and opsins: one rod opsin, RH1 (498 nm), and five cone opsins, SWS1 (370 nm), SWS2B (408 nm), RH2B (498 nm), RH2A (520 nm), and LWS (554 nm). Cones were arranged in a regular mosaic with each single cone surrounded by four double cones. Double cones mainly expressed RH2B (53%) in one member and RH2A (46%) in the other, matching the prevailing light. Single cones expressed SWS1 (89%), which may serve to detect zooplankton, conspecifics and the host anemone. Moreover, a segregated small fraction of single cones coexpressed SWS1 with SWS2B (11%). This novel visual specialisation falls within the region of highest acuity and is suggested to increase the chromatic contrast of Amphiprion akindynos colour patterns, which might improve detection of conspecifics.

S-cone discrimination for stimuli with spatial and temporal chromatic contrast

2008 ◽  
Vol 25 (3) ◽  
pp. 349-354 ◽  
Author(s):  
DINGCAI CAO ◽  
ANDREW J. ZELE ◽  
VIVIANNE C. SMITH ◽  
JOEL POKORNY
Keyword(s):  
Visual System ◽  
Natural Environment ◽  
Stimulus Condition ◽  
Spatial And Temporal Variation ◽  
Natural Scenes ◽  
Test Field ◽  
Temporal Contrast ◽  
Chromatic Contrast ◽  
Laboratory Methods ◽  
Spatio Temporal

In the natural environment, color discriminations are made within a rich context of spatial and temporal variation. In classical laboratory methods for studying chromatic discrimination, there is typically a border between the test and adapting fields that introduces a spatial chromatic contrast signal. Typically, the roles of spatial and temporal contrast on chromatic discrimination are not assessed in the laboratory approach. In this study, S-cone discrimination was measured using stimulus paradigms that controlled the level of spatio-temporal S-cone contrast between the tests and adapting fields. The results indicate that S-cone discrimination of chromaticity differences between a pedestal and adapting surround is equivalent for stimuli containing spatial, temporal or spatial-and-temporal chromatic contrast between the test field and the surround. For a stimulus condition that did not contain spatial or temporal contrast, the visual system adapted to the pedestal instead of the surround. The data are interpreted in terms of a model consistent with primate koniocellular pathway physiology. The paradigms provide an approach for studying the effects of spatial and temporal contrast on discrimination in natural scenes.

scholarly journals Polarization contrasts and their effect on the gaze stabilisation of crustaceans

2021 ◽  
pp. jeb.229898
Author(s):  
Christian Drerup ◽  
Martin J. How
Keyword(s):  
Visual System ◽  
Colour Vision ◽  
Moving Objects ◽  
Visual Scene ◽  
Polarization Vision ◽  
Chromatic Contrast ◽  
Crustacean Species ◽  
The Gaze ◽  
Polarization Of Light ◽  
Do So

Many animals go to great lengths to stabilise their eyes relative to the visual scene and do so to enhance the localisation of moving objects and to functionally partition the visual system relative to the outside world. An important cue that is used to control these stabilisation movements is contrast within the visual surround. Previous studies on insects, spiders and fish have shown that gaze stabilisation is achromatic (= ‘colour-blind’), meaning that chromatic contrast alone (in the absence of apparent intensity contrasts) does not contribute to gaze stabilisation. Following the assumption that polarization vision is analogous in many ways to colour vision, the present study shows that five different crustacean species do not use the polarization of light alone for gaze stabilisation, despite being able to use this modality for detecting predator-like objects. This work therefore suggests that the gaze stabilisation in many crustaceans cannot be elicited by the polarization of light alone.

Author response for "The brain of the African wild dog. IV . The visual system"

2020 ◽  
Author(s):  
Samson Chengetanai ◽  
Adhil Bhagwandin ◽  
Mads F. Bertelsen ◽  
Therese Hård ◽  
Patrick R. Hof ◽  
...  
Keyword(s):  
Visual System ◽  
Author Response ◽  
African Wild Dog ◽  
Wild Dog ◽  
The Brain

Digital differential hysteresis iimage processing displays what the microscope acquires but the eye can't see

1995 ◽  
Vol 53 ◽  
pp. 642-643
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
Image Processing ◽  
Visual System ◽  
High Precision ◽  
Image Data ◽  
Processing Technology ◽  
Output Data ◽  
Contrast Resolution ◽  
Pixel Intensity ◽  
Data Reading ◽  
Hysteresis Properties

Differential hysteresis processing is a new image processing technology that provides a tool for the display of image data information at any level of differential contrast resolution. This includes the maximum contrast resolution of the acquisition system which may be 1,000-times higher than that of the visual system (16 bit versus 6 bit). All microscopes acquire high precision contrasts at a level of <0.01-25% of the acquisition range in 16-bit - 8-bit data, but these contrasts are mostly invisible or only partially visible even in conventionally enhanced images. The processing principle of the differential hysteresis tool is based on hysteresis properties of intensity variations within an image.Differential hysteresis image processing moves a cursor of selected intensity range (hysteresis range) along lines through the image data reading each successive pixel intensity. The midpoint of the cursor provides the output data. If the intensity value of the following pixel falls outside of the actual cursor endpoint values, then the cursor follows the data either with its top or with its bottom, but if the pixels' intensity value falls within the cursor range, then the cursor maintains its intensity value.

Newborn's Preference for Faces

1996 ◽  
Vol 1 (3) ◽  
pp. 200-205 ◽  
Author(s):  
Carlo Umiltà ◽  
Francesca Simion ◽  
Eloisa Valenza
Keyword(s):  
Visual System ◽  
Structural Properties ◽  
Sensory Properties ◽  
Human Face ◽  
System Experiment ◽  
Face Experiment

Four experiments were aimed at elucidating some aspects of the preference for facelike patterns in newborns. Experiment 1 showed a preference for a stimulus whose components were located in the correct arrangement for a human face. Experiment 2 showed a preference for stimuli that had optimal sensory properties for the newborn visual system. Experiment 3 showed that babies directed their attention to a facelike pattern even when it was presented simultaneously with a non-facelike stimulus with optimal sensory properties. Experiment 4 showed the preference for facelike patterns in the temporal hemifield but not in the nasal hemifield. It was concluded that newborns' preference for facelike patterns reflects the activity of a subcortical system which is sensitive to the structural properties of the stimulus.

Sign in / Sign up

Export Citation Format

Share Document