Featured Research

from universities, journals, and other organizations

Early Function Of Specialized Neurons Marks 'First Light' In Retinal Maturation

Date:
June 21, 2005
Source:
Cell Press
Summary:
Researchers have discovered that a set of light-responsive retinal cells that form connections to the circadian clock are functional very early in development, from the day of birth. Although the cells are sensitive to light, they do not participate in image formation, a process that matures later on. The findings show that the non-image-forming pathway is functional at birth, long before development of photosensitivity of the mainstream image-forming visual pathway.

Researchers have discovered that a set of light-responsive retinal cells that form connections to the circadian clock are functional very early in development, from the day of birth. Although the cells are sensitive to light, they do not participate in image formation, a process that matures later on.

The work has been reported in the journal Current Biology by Sumathi Sekaran, of Imperial College London, and colleagues there and at John Hopkins University and the University of Manchester.

The visual system is known to be composed of the classical image-forming pathway, which involves the function of rod and cone photoreceptors, as well as the more recently discovered non-image-forming pathway, which involves specialized neurons called intrinsically photoreceptive retinal ganglion cells (ipRGCs). Although extensive research has characterized the delayed functional maturation of rod and cone photoreception, information pertaining to the development of the ipRGCs has been lacking. It was known, however, that a photopigment present in mature ipRGCs, retinal melanopsin, is expressed long before the classical rod and cone photopigments.

The new research directly studied the functional development of the ipRGCs in mice via a range of approaches, including the examination of melanopsin expression, the physiological recording of ganglion-cell light responses, and the measuring of functional outputs of these cells to higher brain regions. The researchers found that, quite remarkably, the melanopsin-expressing ganglion cells are present in abundance and act as functional photoreceptors from the day of birth, when it has been widely assumed the mouse retina lacks photodetection. At the time of birth, a significant percentage of cells in the retinal ganglion-cell layer express melanopsin and respond to light.

At this early age, these cells provide input conveying light conditions to the suprachiasmatic nucleus, the site of the central circadian pacemaker. The findings show that the non-image-forming pathway is functional at birth, long before development of photosensitivity of the mainstream image-forming visual pathway. It also has implications to the effect of light on early retinal development.

###

The researchers include S. Sekaran, D. Lupi, S.L. Jones, R.G. Foster, and M.W. Hankins of Imperial College London; C.J. Sheely and S. Hattar of Johns Hopkins University; K.-W. Yau of Johns Hopkins University School of Medicine; and R.J. Lucas of University of Manchester. This work was supported by The Wellcome Trust and in part by NSBRI through NASA NCC 9-58.

Sekaran, S., Lupi, D., Jones, S.L., Sheely, C.J., Hattar, S., Yau, K.-W., Lucas, R.J., Foster, R.G., and Hankins, M.W.(2005). Melanopsin-Dependent Photoreception Provides Earliest Light Detection in the Mammalian Retina. DOI 10.1016/j.cub.2005.05.053 Current Biology, Vol. 15, 1099-1107, June 21, 2005. www.current-biology.com


Story Source:

The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.


Cite This Page:

Cell Press. "Early Function Of Specialized Neurons Marks 'First Light' In Retinal Maturation." ScienceDaily. ScienceDaily, 21 June 2005. <www.sciencedaily.com/releases/2005/06/050620003616.htm>.
Cell Press. (2005, June 21). Early Function Of Specialized Neurons Marks 'First Light' In Retinal Maturation. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2005/06/050620003616.htm
Cell Press. "Early Function Of Specialized Neurons Marks 'First Light' In Retinal Maturation." ScienceDaily. www.sciencedaily.com/releases/2005/06/050620003616.htm (accessed October 20, 2014).

Share This



More Health & Medicine News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Microneedle Patch Promises Painless Pricks

Microneedle Patch Promises Painless Pricks

Reuters - Innovations Video Online (Oct. 18, 2014) Researchers at The National University of Singapore have invented a new microneedle patch that could offer a faster and less painful delivery of drugs such as insulin and painkillers. Video provided by Reuters
Powered by NewsLook.com
Raw: Nurse Nina Pham Arrives in Maryland

Raw: Nurse Nina Pham Arrives in Maryland

AP (Oct. 17, 2014) The first nurse to be diagnosed with Ebola at a Dallas hospital walked down the stairs of an executive jet into an ambulance at an airport in Frederick, Maryland, on Thursday. Pham will be treated at the National Institutes of Health. (Oct. 16) Video provided by AP
Powered by NewsLook.com
Raw: Cruise Ship Returns to US Over Ebola Fears

Raw: Cruise Ship Returns to US Over Ebola Fears

AP (Oct. 17, 2014) A Caribbean cruise ship carrying a Dallas health care worker who is being monitored for signs of the Ebola virus is heading back to Texas, US, after being refused permission to dock in Cozumel, Mexico. (Oct. 17) Video provided by AP
Powered by NewsLook.com
Spanish Govt: Four Suspected Ebola Cases in Spain Test Negative

Spanish Govt: Four Suspected Ebola Cases in Spain Test Negative

AFP (Oct. 17, 2014) All four suspected Ebola cases admitted to hospitals in Spain on Thursday have tested negative for the deadly virus in a first round of tests, the government said Friday. Duration: 00:55 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins