Referenced in: none

Automatically associated channels: Kv10.1

Title: Canine retina has a primate fovea-like bouquet of cone photoreceptors which is affected by inherited macular degenerations.

Authors: William A Beltran, Artur V Cideciyan, Karina E Guziewicz, Simone Iwabe, Malgorzata Swider, Erin M Scott, Svetlana V Savina, Gordon Ruthel, Frank Stefano, Lingli Zhang, Richard Zorger, Alexander Sumaroka, Samuel G Jacobson, Gustavo D Aguirre

Journal, date & volume: PLoS ONE, 2014 , 9, e90390

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/24599007

Abstract
Retinal areas of specialization confer vertebrates with the ability to scrutinize corresponding regions of their visual field with greater resolution. A highly specialized area found in haplorhine primates (including humans) is the fovea centralis which is defined by a high density of cone photoreceptors connected individually to interneurons, and retinal ganglion cells (RGCs) that are offset to form a pit lacking retinal capillaries and inner retinal neurons at its center. In dogs, a local increase in RGC density is found in a topographically comparable retinal area defined as the area centralis. While the canine retina is devoid of a foveal pit, no detailed examination of the photoreceptors within the area centralis has been reported. Using both in vivo and ex vivo imaging, we identified a retinal region with a primate fovea-like cone photoreceptor density but without the excavation of the inner retina. Similar anatomical structure observed in rare human subjects has been named fovea-plana. In addition, dogs with mutations in two different genes, that cause macular degeneration in humans, developed earliest disease at the newly-identified canine fovea-like area. Our results challenge the dogma that within the phylogenetic tree of mammals, haplorhine primates with a fovea are the sole lineage in which the retina has a central bouquet of cones. Furthermore, a predilection for naturally-occurring retinal degenerations to alter this cone-enriched area fills the void for a clinically-relevant animal model of human macular degenerations.