SPALVOTO STIMULO SUVOKIMAS REGIMOJO LAUKO PERIFERIJOJE

Psichologija ◽

10.15388/psichol.2008.0.2607 ◽

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.

Download Full-text

Cone opponency in the near peripheral retina

Visual Neuroscience ◽

10.1017/s0952523806233315 ◽

2006 ◽

Vol 23 (3-4) ◽

pp. 503-507 ◽

Cited By ~ 11

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.

Download Full-text

Variant and invariant color perception in the near peripheral retina

Journal of the Optical Society of America A ◽

10.1364/josaa.23.001586 ◽

2006 ◽

Vol 23 (7) ◽

pp. 1586 ◽

Cited By ~ 22

Author(s):

Neil R. A. Parry ◽

Declan J. McKeefry ◽

Ian J. Murray

Keyword(s):

Color Perception ◽

Peripheral Retina

Download Full-text

A Colour Perception Detection Model Based on The Spectral Characterictics

Journal of Mechanical Engineering and Mechatronics ◽

10.33021/jmem.v4i2.856 ◽

2019 ◽

Vol 4 (2) ◽

pp. 87

Author(s):

Irwan Anto Mina

Keyword(s):

Information Needs ◽

Euclidean Distance ◽

Color Image ◽

Detection System ◽

Color Perception ◽

Blue Color ◽

Colour Perception ◽

Detection Tool ◽

Average Color

<p><em>Information needs for one's color perception are needed in the fields of medicine, engineering, astronomy, biomedicine and so on. The demand for accurate assessment of color perception must be met by the perception detection tool used. Ishihara's test, as a perception detection tool that is still used today has insufficient accuracy. This research aims to create a system that can detect a shift in one's color perception, relative to the average color perception of a number of respondents. Through plotting the respondents' perception points, in the CIE coordinate system (Commission International de I'Eclairage) XYZ can be calculated the average euclidean distance, ED, relative to the reference point and the distribution of x and y groups of perception points around the point of reference. Both size, euclidean distance and distribution are used as indicators of average color perception so that an assessment of one's color perception is given based on the results of comparison between color perception points and color perception indicators. The tool used to do the test is Delphi version 7.0 software. the research material used is the RGB (Red, Green, Blue) color image format. The results of a person's color perception study are divided into three levels, namely: (1) "normal" assessment if euclidean (ED) perceptions are smaller than the euclidean (ED) average (2) the "somewhat normal" assessment if the distribution of x and y is smaller rather than the color of perception and the distribution of x and y (3) the assessment is "abnormal" if the color of perception is greater than the max distribution of x and y. A new perception point assessment that is in level one is used to up-date prevailing perception indicators. Up-dating condition constraints affect the quality of the threshold average perception specifically and the quality of the results of the perception detection system in general.</em></p>

Download Full-text

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

Visual Neuroscience ◽

10.1017/s0952523803205058 ◽

2003 ◽

Vol 20 (5) ◽

pp. 511-521 ◽

Cited By ~ 26

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.

Download Full-text

Colour Perception 1978–1997

Perception ◽

10.1068/v970021 ◽

1997 ◽

Vol 26 (1_suppl) ◽

pp. 274-274

Author(s):

J D Mollon

Keyword(s):

Visual System ◽

Dna Sequences ◽

Colour Vision ◽

Ganglion Cells ◽

Major Change ◽

Natural Scenes ◽

Colour Perception ◽

Cone Pigments ◽

The Status ◽

Opponent Processes

In the past twenty years, the spectral sensitivities of the three types of cone have been established with some certainty: direct measurements by microspectrophotometry and electrophysiology are in fair agreement with psychophysical estimates. Particularly significant was the publication of DNA sequences for the four opsins of the human eye, by Jeremy Nathans and colleagues in 1986. This work was soon to transform the understanding of retinitis pigmentosa and other retinal dystrophies, and it has given many insights into the evolution of colour vision; but, curiously, the explanations of dichromacy and anomalous trichromacy have not proved as straightforward as we all expected in 1986. What is clear, however, is that normal colour vision exhibits a genetic polymorphism: much of the intersubject variance in colour matches can be traced to differences in the amino-acid sequence of the opsins for the long-wave and middle-wave cone pigments. The last two decades have seen a major change in the status of opponent processes. In the 1970s it was still common for professors to tell undergraduates that the Young - Helmholtz theory of colour vision held at the receptor level and the Hering theory at the level of the retinal ganglion cells. It is now clear that the chromatically antagonistic processes revealed electrophysiologically and psychophysically in the early visual system do not correspond to the red - green and yellow - blue processes that Hering postulated on the basis of phenomenological observations. The existence of four unique hues is today one of the unexplained mysteries of colour science. In one salient respect, research in colour vision has been changed by instrumental advances. Computer-controlled monitors (though offering splendid pitfalls to the unwary) have allowed the study of spatially and temporally complex chromatic displays, notably in the field of colour constancy. Most recently there has been interest in the chromatic statistics of natural scenes: how well is the visual system matched to the statistics of the world and can it adapt to the gamut of chromaticities present in a given scene?

Download Full-text

Color vision in Attention-Deficit/Hyperactivity Disorder: A pilot visual evoked potential study

10.7287/peerj.preprints.261 ◽

2014 ◽

Author(s):

Soyeon Kim ◽

Tobias Banaschewski ◽

Rosemary Tannock

Keyword(s):

Attention Deficit Hyperactivity Disorder ◽

Color Vision ◽

Attention Deficit ◽

Color Perception ◽

Control Group ◽

Adhd Group ◽

Colour Perception ◽

Hyperactivity Disorder ◽

Dopaminergic Tone ◽

Visual Evoked

Background: Individuals with Attention-Deficit/Hyperactivity Disorder (ADHD) are reported to manifest visual problems (including ophthalmological and color perception problems, particularly for blue-yellow stimuli), but findings are inconsistent. Accordingly, this study investigated visual function and color perception in adolescents with ADHD using VEP. Method: Participants were 31 adolescents (aged 13-18); 16 with a confirmed diagnosis of ADHD, and 15 healthy peers, matched for age, gender, and IQ. All underwent ophthalmological exam, color vision testing (Mollon-Reffin Minimalist Colour Vision Test), as well as electrophysiological testing (color Visual Evoked Potentials; cVEP) which measured the latency and amplitude of the neural P1 response to chromatic stimuli (Blue-Yellow, Red-Green). Result: No group differences were found in clinical measure of color perception or opthalmological exam. However, significantly larger P1 amplitude was found for blue and yellow stimuli, but not red/green stimuli, in the ADHD group compared to controls. Discussion: Larger amplitude in the P1 component for blue-yellow in ADHD group compared to control group may account for no difference in colour perception task. Perhaps activating more resources in early sensory processing (P1) compensated for any underlying problems including compromised retinal input of s-cones due to hypo-dopaminergic tone.

Download Full-text

Environment and culture shape both the colour lexicon and the genetics of colour perception

Scientific Reports ◽

10.1038/s41598-021-98550-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mathilde Josserand ◽

Emma Meeussen ◽

Asifa Majid ◽

Dan Dediu

Keyword(s):

Selection Pressure ◽

Negative Selection ◽

Uv Light ◽

Color Perception ◽

Cultural Complexity ◽

Colour Perception ◽

Green Color ◽

Negative Selection Pressure ◽

Specific Term ◽

Physical Environments

AbstractMany languages express ‘blue’ and ‘green’ under an umbrella term ‘grue’. To explain this variation, it has been suggested that changes in eye physiology, due to UV-light incidence, can lead to abnormalities in blue-green color perception which causes the color lexicon to adapt. Here, we apply advanced statistics on a set of 142 populations to model how different factors shape the presence of a specific term for blue. In addition, we examined if the ontogenetic effect of UV-light on color perception generates a negative selection pressure against inherited abnormal red-green perception. We found the presence of a specific term for blue was influenced by UV incidence as well as several additional factors, including cultural complexity. Moreover, there was evidence that UV incidence was negatively related to abnormal red-green color perception. These results demonstrate that variation in languages can only be understood in the context of their cultural, biological, and physical environments.

Download Full-text