Document Detail


The influence of intrinsically-photosensitive retinal ganglion cells on the spectral sensitivity and response dynamics of the human pupillary light reflex.
MedLine Citation:
PMID:  19850061     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Historically, it was assumed that the light-evoked neural signals driving the human pupillary light reflex (PLR) originated exclusively from rod and cone photoreceptors. However, a novel melanopsin-containing photoreceptive cell class has recently been discovered in the mammalian retina. These intrinsically-photosensitive retinal ganglion cells (ipRGCs) project to the pretectum, the retinorecipient area of the brain responsible for the PLR. This study was therefore designed to examine the relative contribution of rod, cone and the melanopsin photoresponses of ipRGCs to the human PLR. We establish that the melanopsin photoresponse of ipRGCs contributes significantly to the maintenance of half maximal pupilloconstriction in response to light stimuli of 30s or longer, even at low photopic irradiances. Furthermore, we show that the melanopsin photoresponse contributes significantly to three-quarter maximal pupilloconstriction in response to light stimuli as short as 2s. We also demonstrate that cone photoresponses driving pupilloconstriction adapt considerably and contribute little after 30s, but rod photoresponses adapt less and contribute significantly to the maintenance of pupilloconstriction in response to steady-state light stimuli at irradiance levels which are below the threshold of the melanopsin photoresponse.
Authors:
David H McDougal; Paul D Gamlin
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Vision research     Volume:  50     ISSN:  1878-5646     ISO Abbreviation:  Vision Res.     Publication Date:  2010 Jan 
Date Detail:
Created Date:  2009-12-17     Completed Date:  2011-03-14     Revised Date:  2011-09-26    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  72-87     Citation Subset:  IM    
Affiliation:
Laboratory of Autonomic Neurosciences, Pennington Biomedical Research, Center, 6400 Perkins Road, Baton Rouge, LA 70808, United States.
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MeSH Terms
Descriptor/Qualifier:
Adult
Female
Humans
Light
Light Signal Transduction / physiology*
Male
Middle Aged
Reflex, Pupillary / physiology*
Retinal Cone Photoreceptor Cells / physiology
Retinal Ganglion Cells / physiology*
Retinal Rod Photoreceptor Cells / physiology
Rod Opsins / physiology*
Sensory Thresholds / physiology
Grant Support
ID/Acronym/Agency:
EY09380/EY/NEI NIH HHS; P30 EY03039/EY/NEI NIH HHS; R01 EY009380-12/EY/NEI NIH HHS
Chemical
Reg. No./Substance:
0/Rod Opsins; 0/melanopsin
Comments/Corrections

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