scholarly journals What L/M cone-signal pooling is consistent with the Rayleigh matches of carriers of deuteranopia?

2010 ◽  
Vol 8 (6) ◽  
pp. 565-565
Author(s):  
Y. Sun ◽  
S. Shevell
Keyword(s):  
Cone Signal

Brightness In The Photopic Range: Psychophysical Modelling With Blue-sensitive Retinal Signals

2020 ◽  
pp. 9-24
Author(s):  
Peter Bodrogi ◽  
Xue Guo ◽  
Tran Quoc Khanh
Keyword(s):  
Ganglion Cells ◽  
Light Stimulus ◽  
Spectral Radiance ◽  
Psychophysical Experiment ◽  
Retinal Ganglion ◽  
Reasonable Accuracy ◽  
Brightness Perception ◽  
Content Model ◽  
The Difference ◽  
Cone Signal

The brightness perception of a large (41°) uniform visual field was investigated in a visual psychophysical experiment. Subjects assessed the brightness of 20 light source spectra of different chromaticities at two luminance levels, Lv=267.6 cd/m2 and Lv=24.8 cd/m2. The resulting mean subjective brightness scale values were modelled by a combination of the signals of retinal mechanisms: S-cones, rods, intrinsically photosensitive retinal ganglion cells (ipRGCs) and the difference of the L-cone signal and the M-cone signal. A new quantity, “relative spectral blue content”, was also considered for modelling. This quantity was defined as “the spectral radiance of the light stimulus integrated with the range (380–520) nm, relative to luminance”. The “relative spectral blue content” model could describe the subjective brightness perception of the observers with reasonable accuracy.

Interactions between rod and L-cone signals in deuteranopes: Gains and phases

2006 ◽  
Vol 23 (2) ◽  
pp. 201-207 ◽  
Author(s):  
BJØRG ELISABETH KILAVIK ◽  
JAN KREMERS
Keyword(s):  
Phase Difference ◽  
Temporal Frequency ◽  
Detection Thresholds ◽  
Threshold Data ◽  
Delay Difference ◽  
Cone Signal ◽  
Rod Pathway

The dynamics of interactions between rod and L-cone driven signals were studied psychophysically in two deuteranopic observers. Flicker detection thresholds for different ratios of rod to L-cone modulation were measured at temporal frequencies between 1 and 15 Hz. A model, which assumes that rod and L-cone driven signals are vector added, can describe the threshold data adequately. We found that up to about 8–10 Hz temporal frequency, rod and L-cone signals interact additively, whereas at higher frequencies the interaction is subtractive. Rod and L-cone signal strengths depend similarly on temporal frequency and are maximal between 3 and 5 Hz. The phase difference between rod and L-cone signals increases linearly with temporal frequency, indicating that their responses have a delay difference of about 20 to 30 ms, consistent with involvement of the faster rod pathway. The data would suggest a nearly complete additivity of the rod and cone driven signals when using flashed stimuli. But, literature data showed only partial additivity of the two, suggesting that different postreceptoral mechanisms are involved in the two tasks.

Implication of the Yellow Pigment in Dichoptic Colour Mixing

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 122-122
Author(s):  
M L F de Mattiello ◽  
A R Biondini ◽  
H Salinas
Keyword(s):  
Yellow Pigment ◽  
Low Density ◽  
Unanswered Question ◽  
Blue Component ◽  
Cone Signal

Working with colours generated from the three primaries, we found earlier that blue made it difficult to obtain dichoptic mixtures, producing chromatostereopsis and alternation effects which disappeared with increasing eccentricity (1 deg 3 min) or decreasing intensity of the blue component. The unanswered question was: is it true that mixtures with a strong blue component can never be obtained centrally as some authors claim? Therefore, we returned to this subject, using the same methodology and analysing the role that the yellow pigment (YP) would play. First, the samples that previously produced the aforementioned effects were tested, confirming that chromatostereopsis stopped before the alternation. Immediately after that, identical samples were observed through low-density yellow filters that were superposed until both effects ceased. Since the density of the YP of the four participating observers had been previously measured, it was possible to calculate the necessary increase for each one of them, observing that the increment became smaller as the mixtures were displaced towards longer wavelengths. This behaviour indicates a possible function of YP: the attenuation of the blue cone signal to make it compatible with signal from the red and green cones. As the YP varies among observers, this might be the reason why some sources mention that these mixtures can be obtained. If this hypothesis is accepted, this should not be interpreted as a variation in the number of blue receptors through the macula, a variation not necessarily observed in physiology.

scholarly journals Strain variations in cone wavelength peaks in situ during zebrafish development

2019 ◽  
Vol 36 ◽  
Author(s):  
Ralph F. Nelson ◽  
Annika Balraj ◽  
Tara Suresh ◽  
Meaghan Torvund ◽  
Sara S. Patterson
Keyword(s):  
Physiological Measures ◽  
Cone Structure ◽  
Spectral Signal ◽  
Spectral Peaks ◽  
Old Adult ◽  
Multi Wavelength ◽  
Cone Opsins ◽  
Chromatic Processing ◽  
Cone Signal

Abstract There are four cone morphologies in zebrafish, corresponding to UV (U), blue (B), green (G), and red (R)-sensing types; yet genetically, eight cone opsins are expressed. How eight opsins are physiologically siloed in four cone types is not well understood, and in larvae, cone physiological spectral peaks are unstudied. We use a spectral model to infer cone wavelength peaks, semisaturation irradiances, and saturation amplitudes from electroretinogram (ERG) datasets composed of multi-wavelength, multi-irradiance, aspartate-isolated, cone-PIII signals, as compiled from many 5- to 12-day larvae and 8- to 18-month-old adult eyes isolated from wild-type (WT) or roy orbison (roy) strains. Analysis suggests (in nm) a seven-cone, U-360/B1-427/B2-440/G1-460/G3-476/R1-575/R2-556, spectral physiology in WT larvae but a six-cone, U-349/B1-414/G3-483/G4-495/R1-572/R2-556, structure in WT adults. In roy larvae, there is a five-cone structure: U-373/B2-440/G1-460/R1-575/R2-556; in roy adults, there is a four-cone structure, B1-410/G3-482/R1-571/R2-556. Existence of multiple B, G, and R types is inferred from shifts in peaks with red or blue backgrounds. Cones were either high or low semisaturation types. The more sensitive, low semisaturation types included U, B1, and G1 cones [3.0–3.6 log(quanta·μm−2·s−1)]. The less sensitive, high semisaturation types were B2, G3, G4, R1, and R2 types [4.3-4.7 log(quanta·μm−2·s−1)]. In both WT and roy, U- and B- cone saturation amplitudes were greater in larvae than in adults, while G-cone saturation levels were greater in adults. R-cone saturation amplitudes were the largest (50–60% of maximal dataset amplitudes) and constant throughout development. WT and roy larvae differed in cone signal levels, with lesser UV- and greater G-cone amplitudes occurring in roy, indicating strain variation in physiological development of cone signals. These physiological measures of cone types suggest chromatic processing in zebrafish involves at least four to seven spectral signal processing pools.

scholarly journals Multispectral analysis and cone signal modelling of pseudoisochromatic test plates

2013 ◽  
Vol 49 ◽  
pp. 012041 ◽  
Author(s):  
K Luse ◽  
M Ozolinsh ◽  
S Fomins ◽  
A Gutmane
Keyword(s):  
Multispectral Analysis ◽  
Signal Modelling ◽  
Cone Signal

Background-induced flicker enhancement in cat retinal horizontal cells. I. Temporal and spectral properties

1990 ◽  
Vol 64 (2) ◽  
pp. 313-325 ◽  
Author(s):  
R. Pflug ◽  
R. Nelson ◽  
P. K. Ahnelt
Keyword(s):  
Light Adaptation ◽  
Dynamic Range ◽  
Horizontal Cell ◽  
Plexiform Layer ◽  
Horizontal Cells ◽  
Enhancement Effect ◽  
Long Wavelength ◽  
Flicker Response ◽  
Response Enhancement ◽  
Cone Signal

1. Dim backgrounds can enhance small-spot flicker responses of cat retinal horizontal cells by a factor of 2 or more. 2. Intracellular marking with horseradish peroxidase (HRP) reveals that this enhancement effect occurs in--but is not necessarily limited to--the cone-connected, A-type horizontal cell. 3. Flicker amplitudes decrease over a frequency range from 3 to 36 Hz of square-wave photic stimulation. There is little evidence of flicker-response enhancement at 3 Hz. Flicker-response enhancement is typically 2-6 times larger at 35 than at 6 Hz. 4. Inspection of flicker waveforms indicates both a scaling-up of response signals with backgrounds and a distortion composed of 2- to 5-ms-latency decrease, expressed primarily within a quick component of OFF-repolarization. 5. Flicker enhancement first increases as a function of background irradiance and then decreases. The increasing limb has the dynamic range and spectral sensitivity of cat rods (507-nm peak). Enhancement is maintained during rod after-effects. The decreasing limb of the background-versus-intensity function results from light adaptation of cat, long-wavelength (red) cones. 6. The flicker responses themselves peak spectrally at approximately 555 nm and reflect only the activity of cat long-wavelength (red) cones, without evidence of intermixing of other photoreceptor mechanisms. 7. Thus within the first synaptic layer of the cat visual system, rod signals interact with the flicker responses of red cones, both increasing cone-signal amplitudes and modifying cone-signal waveforms. 8. The results are closely analogous to "suppressive rod-cone interaction" (SRCI) as described in human psychophysics. 9. An outer-plexiform-layer circuit involving rods, horizontal cells and cones may mediate rod-induced enhancement of cone flicker. This being the case, notions of horizontal-cell feedback interactions with cones may have to be modified and extended. A specific feedback model is elaborated in the companion paper.

scholarly journals Unexpectedly low UV-sensitivity in a bird, the budgerigar

2014 ◽  
Vol 10 (11) ◽  
pp. 20140670 ◽  
Author(s):  
Johanna Chavez ◽  
Almut Kelber ◽  
Misha Vorobyev ◽  
Olle Lind
Keyword(s):  
Shot Noise ◽  
Light Conditions ◽  
Visual Responses ◽  
Colour Constancy ◽  
Uv Sensitivity ◽  
Background Adaptation ◽  
Behavioural Tests ◽  
Changing Light ◽  
Cone Signal

Photoreceptor adaptation ensures appropriate visual responses during changing light conditions and contributes to colour constancy. We used behavioural tests to compare UV-sensitivity of budgerigars after adaptation to UV-rich and UV-poor backgrounds. In the latter case, we found lower UV-sensitivity than expected, which could be the result of photon-shot noise corrupting cone signal robustness or nonlinear background adaptation. We suggest that nonlinear adaptation may be necessary for allowing cones to discriminate UV-rich signals, such as bird plumage colours, against UV-poor natural backgrounds.

AMPA receptor is involved in transmission of cone signal to ON bipolar cells in carp retina

2004 ◽  
Vol 1002 (1-2) ◽  
pp. 86-93 ◽  
Author(s):  
Hai Huang ◽  
Dong-Gen Luo ◽  
Yin Shen ◽  
Ai-Jun Zhang ◽  
Ru Yang ◽  
...  
Keyword(s):  
Ampa Receptor ◽  
Bipolar Cells ◽  
Cone Signal

Temporal phase response of the short-wave cone signal for color and luminance

1991 ◽  
Vol 31 (5) ◽  
pp. 787-803 ◽  
Author(s):  
Charles F. Stromeyer ◽  
Rhea T. Eskew ◽  
Richard E. Kronauer ◽  
Lothar Spillmann
Keyword(s):  
Short Wave ◽  
Phase Response ◽  
Temporal Phase ◽  
Cone Signal
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