Shades of red: bird-pollinated flowers target the specific colour discrimination abilities of avian vision

2013 ◽  
Vol 198 (1) ◽  
pp. 301-310 ◽  
Author(s):  
Mani Shrestha ◽  
Adrian G. Dyer ◽  
Skye Boyd-Gerny ◽  
Bob B. M. Wong ◽  
Martin Burd
Keyword(s):  
Colour Discrimination ◽  
Avian Vision

scholarly journals Thresholds and noise limitations of colour vision in dim light

2017 ◽  
Vol 372 (1717) ◽  
pp. 20160065 ◽  
Author(s):  
Almut Kelber ◽  
Carola Yovanovich ◽  
Peter Olsson
Keyword(s):  
Shot Noise ◽  
Colour Vision ◽  
Absolute Threshold ◽  
Colour Discrimination ◽  
Dark Noise ◽  
Visual Threshold ◽  
Light Intensities ◽  
Purkinje Shift ◽  
Dim Light ◽  
Receptor Noise

Colour discrimination is based on opponent photoreceptor interactions, and limited by receptor noise. In dim light, photon shot noise impairs colour vision, and in vertebrates, the absolute threshold of colour vision is set by dark noise in cones. Nocturnal insects (e.g. moths and nocturnal bees) and vertebrates lacking rods (geckos) have adaptations to reduce receptor noise and use chromatic vision even in very dim light. In contrast, vertebrates with duplex retinae use colour-blind rod vision when noisy cone signals become unreliable, and their transition from cone- to rod-based vision is marked by the Purkinje shift. Rod–cone interactions have not been shown to improve colour vision in dim light, but may contribute to colour vision in mesopic light intensities. Frogs and toads that have two types of rods use opponent signals from these rods to control phototaxis even at their visual threshold. However, for tasks such as prey or mate choice, their colour discrimination abilities fail at brighter light intensities, similar to other vertebrates, probably limited by the dark noise in cones. This article is part of the themed issue 'Vision in dim light’.

The superstar effect on colour discrimination in the Brazilian cultural labour market

2021 ◽  
Vol 1 (1) ◽  
pp. 1
Author(s):  
Jaqueline Moraes ◽  
Marizélia Ribeiro De Souza ◽  
Thais Alves Da Silva ◽  
Sandro Eduardo Monsueto
Keyword(s):  
Labour Market ◽  
Colour Discrimination

Brightness matching and colour discrimination in young diabetics without retinopathy

1994 ◽  
Vol 34 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Anne Kurtenbach ◽  
Ulrike Wagner ◽  
Andreas Neu ◽  
Ulrich Schiefer ◽  
Michael B. Ranke ◽  
...  
Keyword(s):  
Colour Discrimination

scholarly journals Colour discrimination in dim light by the larvae of the African catfish Clarias gariepinus

2016 ◽  
Vol 64 (2) ◽  
pp. 204-211 ◽  
Author(s):  
Gunzo Kawamura ◽  
Teodora Bagarinao ◽  
Patt Kar Hoo ◽  
Joanevieve Justin ◽  
Leong Seng Lim
Keyword(s):  
Clarias Gariepinus ◽  
African Catfish ◽  
Colour Discrimination ◽  
Dim Light

scholarly journals Comparison of colour discrimination and electroretinography in evaluation of visual pathway dysfunction in aretinopathic IDDM patients.

1995 ◽  
Vol 79 (1) ◽  
pp. 35-37 ◽  
Author(s):  
K J Hardy ◽  
C Fisher ◽  
P Heath ◽  
D H Foster ◽  
J H Scarpello
Keyword(s):  
Visual Pathway ◽  
Colour Discrimination

Development of Blue-Yellow and Red-Green Discriminations in Infants during the First Year of Life

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 235-235
Author(s):  
L I Leushina ◽  
V M Bondarko ◽  
A A Nevskaya
Keyword(s):  
Healthy Subjects ◽  
Risk Group ◽  
Emotional Reaction ◽  
Mean Difference ◽  
The Other ◽  
First Year ◽  
Colour Discrimination ◽  
The Subject ◽  
The Mean ◽  
First Year Of Life

Colour discrimination was investigated in infants aged 4 – 14 months. 250 healthy subjects and 80 subjects with slight defects in basic visual functions (the risk group) participated. A coloured toy was moved in front of the subject and disappeared behind a screen, reappearing after 2 – 3 s at the other side. Sometimes when the toy was hidden, the experimenter replaced it with another one that differed only in colour: yellow was replaced by blue or vice versa (Y/B switch), or red by green or vice versa (R/G switch). The form and size of the toy remained constant. The emotional reaction of surprise showed whether the infant discriminated these colour pairs. The brightness of the stimuli was slightly varied make sure that the infant reacted to the change in colour rather than brightness. About 75% of healthy 4 – 5-month-olds showed good expressive reactions to the Y/B switch, and practically all children did so at 7 – 8 months. The discrimination of red and green develops more slowly: only at 12 months did practically all children show good reactions to the R/G switch. In all children, Y/B discrimination preceded R/G discrimination. The mean difference between the numbers of children discriminating these two pairs was 7.6%. The infants of the risk group were as good as their healthy age-mates in Y/B discrimination, but performed significantly less well on R/G: the mean difference between the numbers discriminating the former but not the latter was 17.0%. Possible reasons for the retardation of chromatic discrimination in the risk group are discussed.

Sign in / Sign up

Export Citation Format

Share Document