The contribution of single and double cones to spectral sensitivity in budgerigars during changing light conditions.

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The contribution of single and double cones to spectral sensitivity in budgerigars during changing light conditions. / Lind, Olle; Chavez, Johanna; Kelber, Almut.

I: Journal of Comparative Physiology A, Vol. 200, Nr. 3, 2014, s. 197-207.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

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TY - JOUR

T1 - The contribution of single and double cones to spectral sensitivity in budgerigars during changing light conditions.

AU - Lind, Olle

AU - Chavez, Johanna

AU - Kelber, Almut

PY - 2014

Y1 - 2014

N2 - Bird colour vision is mediated by single cones, while double cones and rods mediate luminance vision in bright and dim light, respectively. In daylight conditions, birds use colour vision to discriminate large objects such as fruit and plumage patches, and luminance vision to detect fine spatial detail and motion. However, decreasing light intensity favours achromatic mechanisms and eventually, in dim light, luminance vision outperforms colour vision in all visual tasks. We have used behavioural tests in budgerigars (Melopsittacus undulatus) to investigate how single cones, double cones and rods contribute to spectral sensitivity for large (3.4°) static monochromatic stimuli at light intensities ranging from 0.08 to 63.5 cd/m(2). We found no influences of rods at any intensity level. Single cones dominate the spectral sensitivity function at intensities above 1.1 cd/m(2), as predicted by a receptor noise-limited colour discrimination model. Below 1.1 cd/m(2), spectral sensitivity is lower than expected at all wavelengths except 575 nm, which corresponds to double cone function. We suggest that luminance vision mediated by double cones restores visual sensitivity when single cone sensitivity quickly decreases at light intensities close to the absolute threshold of colour vision.

AB - Bird colour vision is mediated by single cones, while double cones and rods mediate luminance vision in bright and dim light, respectively. In daylight conditions, birds use colour vision to discriminate large objects such as fruit and plumage patches, and luminance vision to detect fine spatial detail and motion. However, decreasing light intensity favours achromatic mechanisms and eventually, in dim light, luminance vision outperforms colour vision in all visual tasks. We have used behavioural tests in budgerigars (Melopsittacus undulatus) to investigate how single cones, double cones and rods contribute to spectral sensitivity for large (3.4°) static monochromatic stimuli at light intensities ranging from 0.08 to 63.5 cd/m(2). We found no influences of rods at any intensity level. Single cones dominate the spectral sensitivity function at intensities above 1.1 cd/m(2), as predicted by a receptor noise-limited colour discrimination model. Below 1.1 cd/m(2), spectral sensitivity is lower than expected at all wavelengths except 575 nm, which corresponds to double cone function. We suggest that luminance vision mediated by double cones restores visual sensitivity when single cone sensitivity quickly decreases at light intensities close to the absolute threshold of colour vision.

KW - Single cone

KW - Spectral sensitivity

KW - Chromatic mechanisms

KW - Double cone

KW - Achromatic mechanisms

U2 - 10.1007/s00359-013-0878-7

DO - 10.1007/s00359-013-0878-7

M3 - Article

C2 - 24366429

VL - 200

SP - 197

EP - 207

JO - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology

JF - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology

SN - 1432-1351

IS - 3

ER -