Cone photoreceptor reflectance variation in the northern tree shrew and thirteen-lined ground squirrel. Exp Biol Med (Maywood) 2021 Oct;246(20):2192-2201
Date
07/27/2021Pubmed ID
34308656Pubmed Central ID
PMC8718250DOI
10.1177/15353702211029582Scopus ID
2-s2.0-85111543715 (requires institutional sign-in at Scopus site) 3 CitationsAbstract
In vivo images of human cone photoreceptors have been shown to vary in their reflectance both spatially and temporally. While it is generally accepted that the unique anatomy and physiology of the photoreceptors themselves drives this behavior, the exact mechanisms have not been fully elucidated as most studies on these phenomena have been limited to the human retina. Unlike humans, animal models offer the ability to experimentally manipulate the retina and perform direct in vivo and ex vivo comparisons. The thirteen-lined ground squirrel and northern tree shrew are two emerging animal models being used in vision research. Both models feature cone-dominant retinas, overcoming a key limitation of traditional rodent models. Additionally, each possesses unique but well-documented anatomical differences in cone structure compared to human cones, which can be leveraged to further constrain theoretical models of light propagation within photoreceptors. Here we sought to characterize the spatial and temporal reflectance behavior of cones in these species. Adaptive optics scanning light ophthalmoscopy (AOSLO) was used to non-invasively image the photoreceptors of both species at 5 to 10 min intervals over the span of 18 to 25 min. The reflectance of individual cone photoreceptors was measured over time, and images at individual time points were used to assess the variability of cone reflectance across the cone mosaic. Variability in spatial and temporal photoreceptor reflectance was observed in both species, with similar behavior to that seen in human AOSLO images. Despite the unique cone structure in these animals, these data suggest a common origin of photoreceptor reflectance behavior across species. Such data may help constrain models of the cellular origins of photoreceptor reflectance signals. These animal models provide an experimental platform to further explore the morphological origins of light capture and propagation.
Author List
Gaffney M, Cooper RF, Cava JA, Follett HM, Salmon AE, Freling S, Yu CT, Merriman DK, Carroll JAuthors
Joseph J. Carroll PhD Director, Professor in the Ophthalmology and Visual Sciences department at Medical College of WisconsinRobert F. Cooper Ph.D Assistant Professor in the Biomedical Engineering department at Marquette University
MESH terms used to index this publication - Major topics in bold
AnimalsFemale
Male
Models, Animal
Ophthalmoscopy
Retina
Retinal Cone Photoreceptor Cells
Sciuridae
Time Factors
Tupaia
