 |
| Research article summary (published 30 Dec 2002): |
Color opponency in horizontal cells of the vertebrate retina.
Full Abstract
Chromaticity (C-type) horizontal cells have been studied extensively for more than 40 years since the first recording of such units in the fish retina. C-type horizontal cells are seen in almost every retina of cold-blooded species that contains at least two different spectral types of cone. These cells are characterized by photoresponses of polarity that depends upon the wavelength of the stimulating light. There are two basic varieties of chromaticity horizontal cells, biphasic or triphasic cells. Biphasic cells are characterized by one wavelength in which response polarity reverses and triphasic cells have two wavelengths where response polarity reverses. The neuronal network underlying the genesis of color opponency in C-type horizontal cells has been the subject of debate for many years. It is generally accepted now that cones feed-forward excitatory inputs to horizontal cells which in turn exert inhibitory effects on the cones by negative feedback pathways. C-type horizontal cells belonging to the same class are interconnected via gap junctions to form a tight syncytium. However, the spatial properties of these cells depend upon the polarity of the photoresponse because the membrane resistances of the syncytium change with different inputs. Thus, color opponency in C-type horizontal cells depends on the spatial properties of the stimulating light in addition to its dependence upon wavelength, intensity and ambient illumination. The functional role of C-type horizontal cells is to influence the spatial-chromatic organization of the receptive fields of proximal neurons. Thus, the responsiveness of bipolar cells and ganglion cells to surround illumination depend to a great extent upon the horizontal cells. However, the exact mode whereby horizontal cells can affect the organization of the proximal neurons has yet to be elucidated.
Learn Faster Today Improve your study skills
Author information
Author/s: Twig, Gilad (G); Levy, Hanna (H); Perlman, Ido (I);
Affiliation: Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, P.O. Box 9649, Haifa 31096, Israel.
Journal and publication information
Publication Type: Journal Article; Research Support, Non-U.S. Gov't; Review
Journal: Progress in retinal and eye research (Prog Retin Eye Res), published in England. (Language: eng)
Reference: 2003-Jan; vol 22 (issue 1) : pp 31-68
Dates: Created 2003/02/24; Completed 2003/04/23; Revised 2006/11/15;
PMID: 12597923, status: MEDLINE (last retrieval date: 11/6/2008)
Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.
External Links for this article (including full text providers, if available):
Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.
This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.
MeSH headings (categories)
This article was linked to the MESH Headings shown below.
|
|
Related articles
This article has not been indexed for related articles as yet, however you can still use the live related article search links below.
See a large map of 100+ related articles.