Comparison of human and monkey retinal photoreceptor sampling mosaics

1989 ◽  
Vol 3 (3) ◽  
pp. 281-285 ◽  
Author(s):  
Chander N. Samy ◽  
Joy Hirsch
Keyword(s):  
Macaca Fascicularis ◽  
Focal Length ◽  
Primate Species ◽  
Retinal Eccentricity ◽  
Sampling Strategies ◽  
Human Eye ◽  
Rods And Cones ◽  
Retinal Photoreceptor ◽  
Photoreceptor Mosaic ◽  
Human Density

AbstractWe test the hypothesis that the diameters of foveal and near-foveal rods and cones for one well-studied human photoreceptor mosaic and one well-studied monkey photoreceptor mosaic (Macaca fascicularis) a scaled relative to focal length. We conclude that this hypothesis is not supported. Rather than being scali proportionally, the sizes of the rods and cones, respectively, are nearly equivalent for both the human ar monkey resulting in an effectively finer retinal grain for the larger human eye. Furthermore, the human density exceeds the monkey rod density beyond about 1 deg of retinal eccentricity. These results suggest variation across primate species is reflected in retinal sampling strategies.

Protein Sorting in Healthy and Diseased Photoreceptors

2019 ◽  
Vol 5 (1) ◽  
pp. 73-98 ◽  
Author(s):  
Yoshikazu Imanishi
Keyword(s):  
Signal Transduction ◽  
Membrane Protein ◽  
Outer Segment ◽  
Protein Sorting ◽  
Rods And Cones ◽  
Retinal Photoreceptor ◽  
Photoreceptor Neurons ◽  
Cellular Compartments ◽  
G Protein Coupled ◽  
Distinct Membrane

Rods and cones are retinal photoreceptor neurons required for our visual sensation. Because of their highly polarized structures and well-characterized processes of G protein–coupled receptor–mediated phototransduction signaling, these photoreceptors have been excellent models for studying the compartmentalization and sorting of proteins. Rods and cones have a modified ciliary compartment called the outer segment (OS) as well as non-OS compartments. The distinct membrane protein compositions between OS and non-OS compartments suggest that the OS is separated from the rest of the cellular compartments by multiple barriers or gates that are selectively permissive to specific cargoes. This review discusses the mechanisms of protein sorting and compartmentalization in photoreceptor neurons. Proper sorting and compartmentalization of membrane proteins are required for signal transduction and transmission. This review also discusses the roles of compartmentalized signaling, which is compromised in various retinal ciliopathies.

scholarly journals Estimating densities and spatial distribution of a commensal primate species, the long‐tailed macaque ( Macaca fascicularis )

2019 ◽  
Vol 1 (9) ◽  
Author(s):  
Malene F. Hansen ◽  
Ventie A. Nawangsari ◽  
Floris M. Beest ◽  
Niels M. Schmidt ◽  
Agustin Fuentes ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Macaca Fascicularis ◽  
Primate Species

Relation of Brightness to Threshold for Light-Adapted and Dark-Adapted Rods and Cones: Effects of Retinal Eccentricity and Target Size

Perception ◽  
1980 ◽  
Vol 9 (6) ◽  
pp. 633-650 ◽  
Author(s):  
Bruce Drum
Keyword(s):  
Retinal Ganglion Cells ◽  
Channel Model ◽  
Ganglion Cells ◽  
The Other ◽  
Target Size ◽  
Retinal Eccentricity ◽  
Retinal Ganglion ◽  
Threshold Functions ◽  
Rods And Cones ◽  
Matching Procedure

‘Equal-brightness' functions of retinal eccentricity and target diameter were measured by a matching procedure, and compared with the corresponding threshold functions for four different adaptation conditions: light-adapted cones (LAC), dark-adapted cones (DAC), light-adapted rods (LAR) and dark-adapted rods (DAR). The separation between log brightness matches and log thresholds decreased with eccentricity and increased with target size for all adaptation conditions, but overall separation was substantially greater for the DAR condition than for the other three. A two-channel model of achromatic brightness is proposed to explain the results. The model assumes ‘strong’ and ‘weak’ channels, which contribute unequally to brightness. These channels are tentatively identified with tonic and phasic classes of retinal ganglion cells.

scholarly journals Food hardness and stone tool weight in wild primate nut-cracking

2018 ◽  
Author(s):  
Michael Haslam
Keyword(s):  
Pan Troglodytes ◽  
Macaca Fascicularis ◽  
Primate Species ◽  
Stone Tool ◽  
Pan Troglodytes Verus ◽  
Crack Open ◽  
Hardness Curve ◽  
Species Overlap ◽  
In The Wild ◽  
Nut Cracking

AbstractThis study presents data on average stone tool weights and the hardness of foods processed by the three known stone-tool-using primate species: Burmese long-tailed macaques (Macaca fascicularis aurea), bearded capuchins (Sapajus libidinosus) and Western chimpanzees (Pan troglodytes verus). Each of these primates uses stone hammers to crack open nuts in the wild, making them suitable for inter-species behavioural comparison. This work draws on published results to identify a distinct difference in the tool weight/food hardness curve between chimpanzees and the two monkey taxa, with the latter reaching an asymptote in mean tool weight of just over 1 kg regardless of increasing food hardness. In contrast, chimpanzees rapidly increase their tool weight in response to increasing hardness, selecting average masses over 5 kg to process the hardest nuts. Species overlap in their preference for tools of 0.8-1 kg for opening foods of hardness 2-3 kN, suggesting that this conjunction may represent a primate stone-tool-use optimum.

Infinitely Distant

2021 ◽  
pp. 143-146
Author(s):  
Stephen R. Wilk
Keyword(s):  
Optical System ◽  
Focal Length ◽  
Human Eye ◽  
Darkened Room ◽  
Collimated Beam

A conundrum—you can estimate the focal length of a positive lens by using it to project the image of a distant scene onto the wall in a darkened room. But if you try to do it by placing the lens, a focal length away from an illuminated object and looking for the point where to produces a lens-filling collimated beam, you don’t get the correct length. When you’re figuring out the behavior of images in an optical system meant to be viewed with the human eye, don’t forget to include the optics of the eye itself.

scholarly journals Modulation transfer of the human eye as a function of retinal eccentricity

1993 ◽  
Vol 10 (2) ◽  
pp. 201 ◽  
Author(s):  
Rafael Navarro ◽  
David R. Williams ◽  
Pablo Artal
Keyword(s):  
Retinal Eccentricity ◽  
Modulation Transfer ◽  
Human Eye

Causes of obesity in captive cynomolgus macaques: influence of body condition, social and management factors on behaviour around feeding

2012 ◽  
Vol 46 (3) ◽  
pp. 193-199 ◽  
Author(s):  
S A Bauer ◽  
D L Pearl ◽  
K E Leslie ◽  
J Fournier ◽  
P V Turner
Keyword(s):  
Social Interactions ◽  
Body Condition ◽  
Macaca Fascicularis ◽  
Prospective Observational Study ◽  
Primate Species ◽  
Activity Levels ◽  
Cynomolgus Macaques ◽  
More Care ◽  
Positive Social Interaction ◽  
The Relationship

Similar to other primate species, captive cynomolgus macaques ( Macaca fascicularis) are prone to becoming overweight. The relationship between body condition and feeding behaviour in group-housed animals has not been reported. This study evaluated the effect of daily feeding routines on behaviour patterns in cynomolgus macaques to determine whether overweight macaques displayed different behaviours and activity levels. In this prospective observational study, 16 macaques ( m = 4, f = 12) from four separate troops ( n = 4 per troop) were selected from a colony of 165 animals. Observational data were collected over six months during morning and afternoon feedings by scan sampling. Behaviours of interest included foraging, eating, aggressive and positive social interactions, inactivity and physical activities. Multivariable mixed logistic regression modelling was used for data analysis. Results indicated that overweight animals were more likely to be inactive, dominant animals had increased probabilities of eating compared with non-dominants, and aggressive behaviours were more likely to occur in the morning and before feeding, suggesting feeding anticipation. Positive social interaction before feeding was seen and may be a strategy used to avoid aggressive encounters around food resources. Individual animal caregivers had an unintentional impact on behaviour, as decreased eating and an increase in inactivity were noted when certain individuals fed animals. These findings illustrate the complexities of feeding group-housed cynomolgus macaques to avoid overweight body condition. Feeding routines may require more care and attention to distribute food in a way that ensures equitable food intake among troop animals, while not disturbing group cohesion.

scholarly journals A THEORY OF VISUAL INTENSITY DISCRIMINATION

1935 ◽  
Vol 18 (5) ◽  
pp. 767-789 ◽  
Author(s):  
Selig Hecht
Keyword(s):  
Inflection Point ◽  
Red Light ◽  
Intensity Discrimination ◽  
Continuous Curve ◽  
Yellow Light ◽  
Human Eye ◽  
Rods And Cones ◽  
Double Curve ◽  
Small Test ◽  
The Moment

1. A theory of visual intensity discrimination is proposed in terms of the photochemical events which take place at the moment when a photosensory system already adapted to the intensity I is exposed to the just perceptibly higher intensity I+ΔI. Unlike previous formulations this theory predicts that the fraction ΔI/I, after rapidly decreasing as I increases, does not increase again at high intensities, but reaches a constant value which is maintained even at the highest intensities. 2. The theory describes quantitatively the intensity discrimination data of Drosophila, of the bee, and of Mya. 3. With some carefully considered exceptions the intensity discrimination data of the human eye fall into two classes: those with small test areas or with red light, which form a single continuous curve describing the function of the retinal cones alone, and those with larger areas, and with white, orange, and yellow light, which form a double curve showing a clear inflection point, and represent the separate function of the rods at intensities below the inflection point and of the cones at intensities above it. 4. The theory describes all these data quantitatively by treating the rods and cones as two independently functioning photosensory systems in accordance with the well established duplicity idea. 5. In terms of the theory the data of intensity discrimination give critical information about the order of both the photochemical and dark reactions in each photosensory system. The reactions turn out to be variously monomolecular and bimolecular for the different animals.

scholarly journals Reliability and Agreement Between Metrics of Cone Spacing in Adaptive Optics Images of the Human Retinal Photoreceptor Mosaic

2017 ◽  
Vol 58 (7) ◽  
pp. 3127 ◽  
Author(s):  
Daniela Giannini ◽  
Giuseppe Lombardo ◽  
Letizia Mariotti ◽  
Nicholas Devaney ◽  
Sebastiano Serrao ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Retinal Photoreceptor ◽  
Photoreceptor Mosaic

scholarly journals Divergent strategies in faeces avoidance between two cercopithecoid primates

2020 ◽  
Vol 7 (3) ◽  
pp. 191861 ◽  
Author(s):  
Cécile Sarabian ◽  
Barthélémy Ngoubangoye ◽  
Andrew J. J. MacIntosh
Keyword(s):  
Macaca Fascicularis ◽  
Animal Species ◽  
Experimental Approach ◽  
Food Contamination ◽  
Olfactory Cues ◽  
Primate Species ◽  
Infectious Agents ◽  
Evolutionary Time ◽  
Mandrillus Sphinx ◽  
Consumption Rates

Parasites constitute a major selective pressure which has shaped animal behaviour through evolutionary time. One adaption to parasites consists of recognizing and avoiding substrates or cues that indicate their presence. Among substrates harbouring infectious agents, faeces are known to elicit avoidance behaviour in numerous animal species. However, the function and mechanisms of faeces avoidance in non-human primates has been largely overlooked by scientists. In this study, we used an experimental approach to investigate whether aversion to faeces in a foraging context is mediated by visual and olfactory cues in two cercopithecoid primates: mandrills ( Mandrillus sphinx ) and long-tailed macaques ( Macaca fascicularis ). Visual and olfactory cues of faeces elicited lower food consumption rates in mandrills and higher food manipulation rates in long-tailed macaques. Both results support the infection-avoidance hypothesis and confirm similar tendencies observed in other primate species. More studies are now needed to investigate the divergence of avoidance strategies observed in non-human primates regarding food contamination.

Sign in / Sign up

Export Citation Format

Share Document