Variant and invariant color perception in the near peripheral retina

2006 ◽  
Vol 23 (7) ◽  
pp. 1586 ◽  
Author(s):  
Neil R. A. Parry ◽  
Declan J. McKeefry ◽  
Ian J. Murray
Keyword(s):  
Color Perception ◽  
Peripheral Retina

Cone opponency in the near peripheral retina

2006 ◽  
Vol 23 (3-4) ◽  
pp. 503-507 ◽  
Author(s):  
I.J. MURRAY ◽  
N.R.A. PARRY ◽  
D.J. McKEEFRY
Keyword(s):  
Color Perception ◽  
Peripheral Retina ◽  
Test Target ◽  
Second Stage ◽  
Physiological Differences

Changes of color perception in the peripheral field are measured using an asymmetric simultaneous matching paradigm. The data confirm previous observations in that saturation changes can be neutralized if the test target is increased in size. However, this compensation does not apply to hue shifts. We show that some hues remain unchanged with eccentricity whereas others exhibit substantial changes. Here the color shifts are plotted in terms of a second-stage cone opponent model. The data suggest that the S-L+M channel is more robust to increasing eccentricity than the L-M channel. Observations are interpreted in terms of the known underlying morphological and physiological differences in these channels.

Chromatic detection and discrimination in the periphery: A postreceptoral loss of color sensitivity

2003 ◽  
Vol 20 (5) ◽  
pp. 511-521 ◽  
Author(s):  
JESSICA R. NEWTON ◽  
RHEA T. ESKEW
Keyword(s):  
Visual Field ◽  
Color Perception ◽  
Bipolar Cells ◽  
Peripheral Visual Field ◽  
Peripheral Retina ◽  
Retinal Ganglion ◽  
Noise Masking ◽  
Green Color ◽  
Color Sensitivity ◽  
Masked Detection

The peripheral visual field is marked by a deterioration in color sensitivity, sometimes attributed to the random wiring of midget bipolar cells to cone photoreceptors in the peripheral retina (Mullen, 1991; Mullen & Kingdom, 1996). Using psychophysical methods, we explored differences in the sensitivity of peripheral color mechanisms with detection and discrimination of 2-deg spots at 18-deg eccentricity, and find evidence for a postreceptoral locus for the observed loss in sensitivity. As shown before, observers' sensitivity to green was lower than to red in the periphery, although the magnitude of this effect differed across observers. These results suggest that the asymmetry in peripheral sensitivity occurs at a postreceptoral site, possibly a cortical one. In addition, noise masking was used to determine the cone inputs to the peripheral color mechanisms. The masked detection contours indicate that the red and green mechanisms in the periphery respond to the linear difference of approximately equally weighted L- and M-cone contrasts, just as they do in the fovea. Thus, if the midget retinal ganglion system is responsible for red/green color perception in the fovea, it is likely to be responsible at 18-deg eccentricity as well.

scholarly journals SPALVOTO STIMULO SUVOKIMAS REGIMOJO LAUKO PERIFERIJOJE

Psichologija ◽  
2008 ◽  
Vol 38 ◽  
pp. 19-28
Author(s):  
Declan J. McKeefry ◽  
Neil R. A. Parry ◽  
Ian J. Murray ◽  
Athanasios Panorgias
Keyword(s):  
Color Perception ◽  
Peripheral Retina ◽  
Colour Perception ◽  
Opponent Processes

Mes tyrėme, kaip pakinta stimulo spalvos suvokimas, kai stimulas matomas regimojo lauko centre ir kai periferijoje. Lygindami L-M ir S-(L+M) oponentinių sistemų, gaunančių signalus iš centrinės ir periferinės tinklainės dalies, aktyvumą, nustatėme, kad spalvų suvokimo pokyčiai atspindi L-M oponentinės sistemos aktyvumo silpnėjimą periferijoje. S kūgelių įtaka oponentinės sistemos aktyvumui kinta mažiau negu L-M kūgelių. Taigi, dviejų oponentinių sistemų santykinė įtaka spalvos suvokimui periferijoje ir centre pakinta. Straipsnyje tiriama, kokią reikšmę šiems pokyčiams turi tinklainėje ir smegenų žievėje vykstantys procesai. Pagrindiniai žodžiai: spalva, suvokimas, oponentinės ląstelės, centrinė ir periferinė tinklainė.The Perception of Chromatic Stimuli in the Peripheral Human RetinaDeclan J. McKeefry, Neil R. A. Parry, Ian J. Murray, Athanasios Panorgias SummaryWe have studied the changes that occur in human colour perception in the peripheral retina. By modelling the magnitude of activation produced in the L-M and S-(L+M) cone-opponent systems for matched para-foveal and peripheral chromatic stimuli, we have found that variations in perceived appearance are mirrored by a reduction in function of the L-M opponent system. The operation of the S-cone opponent system is affected to a much lesser degree, implying that there is a changing pattern of predominance between the two cone-opponent mechanisms in the peripheral retina. We will explore possible retinal and cortical bases for these changes.Key words: color, perception, opponent processes, central and peripheral retina.

COLOR PERCEPTION OF SMALL STIMULI WITH CENTRAL VISION. (Rep. No. 257).

1954 ◽  
Author(s):  
Beverly Hillmann ◽  
Katherine Connolly ◽  
Dean Farnsworth
Keyword(s):  
Color Perception ◽  
Central Vision

Hearing words changes color perception: Facilitation of color discrimination by verbal and visual cues

2017 ◽  
Author(s):  
Lewis Forder ◽  
Gary Lupyan
Keyword(s):  
Visual Cues ◽  
Color Word ◽  
Color Perception ◽  
Color Discrimination ◽  
Target Color ◽  
Discrimination Accuracy ◽  
Verbal Cues ◽  
The Moment

As part of learning some languages, people learn to name colors using categorical labels such as “red”, “yellow”, and “green”. Such labeling clearly facilitates communicating about colors, but does it also impact color perception? We demonstrate that simply hearing color words enhances categorical color perception, improving people’s accuracy in discriminating between simultaneously presented colors in an untimed task. Immediately after hearing a color word participants were better able to distinguish between colors from the named category and colors from nearby categories. Discrimination was also enhanced between typical and atypical category members. Verbal cues slightly decreased discrimination accuracy between two typical shades of the named color. In contrast to verbal cues, a preview of the target color, an arguably more informative cue, failed to yield any changes to discrimination accuracy. The finding that color words strongly affect color discrimination accuracy suggests that categorical color perception may be due to color representations being augmented in-the-moment by language.

Drusen in the Peripheral Retina of the Alzheimer’s Eye

2018 ◽  
Vol 15 (8) ◽  
pp. 743-750 ◽  
Author(s):  
Kresimir Ukalovic ◽  
Sijia Cao ◽  
Sieun Lee ◽  
Qiaoyue Tang ◽  
Mirza Faisal Beg ◽  
...  
Keyword(s):  
Peripheral Retina ◽  
Amyloid Angiopathy ◽  
Temporal Region ◽  
Future Studies ◽  
Eye Tissues ◽  
Neuropathological Diagnosis ◽  
Ocular Imaging ◽  
Cerebral Amyloid ◽  
The Brain ◽  
Oil Red O

Background: Recent work on Alzheimer's disease (AD) diagnosis focuses on neuroimaging modalities; however, these methods are expensive, invasive, and not available to all patients. Ocular imaging of biomarkers, such as drusen in the peripheral retina, could provide an alternative method to diagnose AD. Objective: This study compares macular and peripheral drusen load in control and AD eyes. Methods: Postmortem eye tissues were obtained from donors with a neuropathological diagnosis of AD. Retina from normal donors were processed and categorized into younger (<55 years) and older (>55 years) groups. After fixation and dissection, 3-6 mm punches of RPE/choroid were taken in macular and peripheral (temporal, superior, and inferior) retinal regions. Oil red O positive drusen were counted and grouped into two size categories: small (<63 μm) and intermediate (63-125 μm). Results: There was a significant increase in the total number of macular and peripheral hard drusen in older, compared to younger, normal eyes (p<0.05). Intermediate hard drusen were more commonly found in the temporal region of AD eyes compared to older normal eyes, even after controlling for age (p<0.05). Among the brain and eye tissues from AD donors, there was a significant relationship between cerebral amyloid angiopathy (CAA) severity and number of temporal intermediate hard drusen (r=0.78, p<0.05). Conclusion: Imaging temporal drusen in the eye may have benefit for diagnosing and monitoring progression of AD. Our results on CAA severity and temporal intermediate drusen in the AD eye are novel. Future studies are needed to further understand the interactions among CAA and drusen formation.

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