Cone opponency in the near peripheral retina

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.

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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

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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.

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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.

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Altered Fine Structure of B Lymphocytes Correlated with Defective Terminal Differentiation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010007237x ◽

1973 ◽

Vol 31 ◽

pp. 386-387

Author(s):

Dale E. Bockman ◽

L. Y. Frank Wu ◽

Alexander R. Lawton ◽

Max D. Cooper

Keyword(s):

Immune Deficiency ◽

B Lymphocytes ◽

Plasma Cells ◽

Present Report ◽

Specific Antigen ◽

Terminal Differentiation ◽

Second Stage ◽

Two Stages ◽

Deficiency Diseases ◽

Cell Line Generation

B-lymphocytes normally synthesize small amounts of immunoglobulin, some of which is incorporated into the cell membrane where it serves as receptor of antigen. These cells, on contact with specific antigen, proliferate and differentiate to plasma cells which synthesize and secrete large quantities of immunoglobulin. The two stages of differentiation of this cell line (generation of B-lymphocytes and antigen-driven maturation to plasma cells) are clearly separable during ontogeny and in some immune deficiency diseases. The present report describes morphologic aberrations of B-lymphocytes in two diseases in which second stage differentiation is defective.

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Cryomicroscopy of multiphase latices

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089615 ◽

1991 ◽

Vol 49 ◽

pp. 1060-1061

Author(s):

O. L. Shaffer ◽

M.S. El-Aasser ◽

C. L. Zhao ◽

M. A. Winnik ◽

R. R. Shivers

Keyword(s):

Electron Microscopy ◽

Radiation Damage ◽

Freeze Fracture ◽

Particle Morphology ◽

Second Stage ◽

Transmission Electron ◽

Important Approach ◽

Carbon Coated ◽

Preparation Techniques

Transmission electron microscopy is an important approach to the characterization of the morphology of multiphase latices. Various sample preparation techniques have been applied to multiphase latices such as OsO4, RuO4 and CsOH stains to distinguish the polymer phases or domains. Radiation damage by an electron beam of latices imbedded in ice has also been used as a technique to study particle morphology. Further studies have been developed in the use of freeze-fracture and the effect of differential radiation damage at liquid nitrogen temperatures of the latex particles embedded in ice and not embedded.Two different series of two-stage latices were prepared with (1) a poly(methyl methacrylate) (PMMA) seed and poly(styrene) (PS) second stage; (2) a PS seed and PMMA second stage. Both series have varying amounts of second-stage monomer which was added to the seed latex semicontinuously. A drop of diluted latex was placed on a 200-mesh Formvar-carbon coated copper grid.

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Observations on the growth of barium bismuth oxide thin films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100120783 ◽

1992 ◽

Vol 50 (1) ◽

pp. 76-77

Author(s):

M G. Norton ◽

E.S. Hellman ◽

E.H. Hartford ◽

C.B. Carter

Keyword(s):

Substrate Temperature ◽

Deposition Process ◽

Nucleation Layer ◽

Second Stage ◽

Device Applications ◽

High Transition ◽

Substrate Temperatures ◽

Oriented Material ◽

Barium Bismuth ◽

Superconductor Device

The bismuthates (for example, Ba1-xKxBiO3) represent a class of high transition temperature superconductors. The lack of anisotropy and the long coherence length of the bismuthates makes them technologically interesting for superconductor device applications. To obtain (100) oriented Ba1-xKxBiO3 films on (100) oriented MgO, a two-stage deposition process is utilized. In the first stage the films are nucleated at higher substrate temperatures, without the potassium. This process appears to facilitate the formation of the perovskite (100) orientation on (100) MgO. This nucleation layer is typically between 10 and 50 nm thick. In the second stage, the substrate temperature is reduced and the Ba1-xKxBiO3 is grown. Continued growth of (100) oriented material is possible at the lower substrate temperature.

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Second stage of labor in the age of epidural anesthesia

Journal of the Society for Gynecologic Investigation ◽

10.1016/s1071-5576(97)86622-1 ◽

1998 ◽

Vol 5 (1) ◽

pp. 171A-171A

Author(s):

E XENAKIS ◽

J PIPER ◽

M MCFARLAND ◽

C SUITER ◽

O LANGER

Keyword(s):

Epidural Anesthesia ◽

Second Stage Of Labor ◽

Second Stage

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The Gender Typicality of Faces and Its Impact on Visual Processing and on Hiring Decisions

Experimental Psychology (formerly Zeitschrift für Experimentelle Psychologie) ◽

10.1027/1618-3169/a000217 ◽

2013 ◽

Vol 60 (6) ◽

pp. 444-452 ◽

Cited By ~ 8

Author(s):

Lisa von Stockhausen ◽

Sara Koeser ◽

Sabine Sczesny

Keyword(s):

Visual Processing ◽

Past Research ◽

Visual Exploration ◽

Facial Appearance ◽

Leadership Roles ◽

Hiring Decisions ◽

Leadership Selection ◽

Gender Typicality ◽

Second Stage ◽

The Feminine

Past research has shown that the gender typicality of applicants’ faces affects leadership selection irrespective of a candidate’s gender: A masculine facial appearance is congruent with masculine-typed leadership roles, thus masculine-looking applicants are hired more certainly than feminine-looking ones. In the present study, we extended this line of research by investigating hiring decisions for both masculine- and feminine-typed professional roles. Furthermore, we used eye tracking to examine the visual exploration of applicants’ portraits. Our results indicate that masculine-looking applicants were favored for the masculine-typed role (leader) and feminine-looking applicants for the feminine-typed role (team member). Eye movement patterns showed that information about gender category and facial appearance was integrated during first fixations of the portraits. Hiring decisions, however, were not based on this initial analysis, but occurred at a second stage, when the portrait was viewed in the context of considering the applicant for a specific job.

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