Retinal cells thoughts to be the same are not: study
July 25, 2011 in Medical research
The old adage "Looks can be deceiving" certainly rings true when it comes to people. But it is also accurate when describing special light-sensing cells in the eye, according to a Johns Hopkins University biologist.
In a study recently published in Nature, a team led by Samer Hattar of the Department of Biology at the Krieger School of Arts and Sciences and Tudor Badea at the National Eye Institute found that these cells, which were thought to be identical and responsible for both setting the body's circadian rhythm and the pupil's reaction to light and darkness, are actually two different cells, each responsible for one of those tasks.
"In biology, as in life, you can't always trust what you see," said Hattar. "You have to delve deep to find out what's really going on. This study has shown that two structurally similar neurons are actually quite different and distinct, communicate with different regions of the brain and influence different visual functions."
The findings are significant, Hattar said, because doctors sometimes use pupillary light reflex (the pupil's response to light and darkness) as a way of diagnosing patients who may have sleep problems, and those clinicians now must recognize that the cells controlling pupillary response and those controlling the sleep-wake cycle are different.
"Although the diagnosis may still be valid most of the time, it is important to remember that disrupted pupillary light response with normal sleep wake cycles or the opposite is possible, and caution should be exercised if clinicians only use pupillary light reflex for diagnosis purposes for deficits in non-image forming visual functions," explained Shih-Kuo (Alen) Chen, a post-doctoral fellow in the Department of Biology and co-author of the Nature article.
Hattar's research focuses on these special light-sensitive cells and how they regulate the physiology and behavior of mammals.
"In human beings, light has an impact on many of our physiological functions, including sleep and mood," he explains. "We are interested in the cellular, molecular and behavioral pathways by which light has an impact on us, independent of how and what we literally 'see' with our eyes. This includes setting our internal, biological clock to the day and night and constricting our pupils to control the amount of light coming through to our retinas."
In a previous study, Hattar's team revealed that these cells -- called "intrinsically photosensitive Retinal Ganglion Cells" -- also play a role in image formation. Formerly, it was thought that the ipRGCs' role was limited to sleep-wake cycles and pupillary responses.
More information: www.nature.com/nat… re10206.html
Provided by
Johns Hopkins University
-
Tick tock: Rods help set internal clocks, biologist says
Sep 17, 2010 |
not rated yet |
0
-
Blind mice can 'see' thanks to special retinal cells
Jul 14, 2010 |
not rated yet |
0
-
More than meets the eye to staying awake, alert
May 13, 2010 |
not rated yet |
0
-
Scientists Uncover Inner Workings of Rare Eye Cells
Jan 27, 2005 |
not rated yet |
0
-
Cells in eye could help control sleep
Aug 18, 2008 |
not rated yet |
0
-
Motion perception revisited: High Phi effect challenges established motion perception assumptions
Apr 23, 2013 |
3 / 5 (2) |
2
-
Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update)
Apr 02, 2013 |
4.5 / 5 (11) |
5
-
The visual system as economist: Neural resource allocation in visual adaptation
Mar 30, 2013 |
5 / 5 (2) |
9
-
Separate lives: Neuronal and organismal lifespans decoupled
Mar 27, 2013 |
4.9 / 5 (8) |
0
-
Sizing things up: The evolutionary neurobiology of scale invariance
Feb 28, 2013 |
4.8 / 5 (10) |
14
-
Why is zone 1 in liver more prone to ischemic injury?
May 23, 2013
-
How can there be villous adenoma in colon, if there are no villi there
May 22, 2013
-
How can there be a term called "intestinal metaplasia" of stomach
May 21, 2013
-
Pressure-volume curve: Elastic Recoil Pressure don't make sense
May 18, 2013
-
If you became brain-dead, would you want them to pull the plug?
May 17, 2013
-
MRI bill question
May 15, 2013
- More from Physics Forums - Medical Sciences
More news stories
Study reveals new mechanism for estrogen suppression of liver lipid synthesis
By discovering the new mechanism by which estrogen suppresses lipid synthesis in the liver, UC Irvine endocrinologists have revealed a potential new approach toward treating certain liver diseases.
Medical research
19 hours ago |
not rated yet |
0
|
MRI-based measurement helps predict vascular disease in the brain
Aortic arch pulse wave velocity, a measure of arterial stiffness, is a strong independent predictor of disease of the vessels that supply blood to the brain, according to a new study published in the June issue the journal ...
Medical research
19 hours ago |
not rated yet |
0
Antibiotics: A new understanding of sulfonamide nervous system side effects
Since the discovery of Prontosil in 1932, sulfonamide antibiotics have been used to combat a wide spectrum of bacterial infections, from acne to chlamydia and pneumonia. However, their side effects can include serious neurological ...
Medical research
21 hours ago |
not rated yet |
0
|
Scientists discover molecule triggers sensation of itch
Scientists at the National Institutes of Health report they have discovered in mouse studies that a small molecule released in the spinal cord triggers a process that is later experienced in the brain as ...
Medical research
21 hours ago |
5 / 5 (2) |
0
|
Discarded immune cells induce the relocation of stem cells
Spanish researchers have discovered that the daily clearance of neutrophils from the body stimulates the release of hematopoietic stem cells from the bone marrow into the bloodstream, according to a report published today ...
Medical research
23 hours ago |
5 / 5 (2) |
0
Engineered cytomegalovirus protects monkeys from HIV equivalent
(Medical Xpress)—A new study by researchers in the US has shown that an ancient virus can be modified to help in the fight against the simian immunodeficiency virus SIV, which is the equivalent in monkeys ...
Controlling mood through the motions of mitochondria
(Medical Xpress)—Regulating the distribution of power in neurons is done by a system that makes the national electric grid look simple by comparison. Each neuron has several thousand mitochondria confined ...
New neuron formation could increase capacity for new learning, at the expense of old memories
New research presented today shows that formation of new neurons in the hippocampus - a brain region known for its importance in learning and remembering - could cause forgetting of old memories by causing a reorganization ...
Are there atheists in foxholes? Study says they're the minority
Ernie Pyle – an iconic war correspondent in World War II – reportedly said "There are no atheists in foxholes." A new joint study between two brothers at Cornell and Virginia Wesleyan found that only ...
Scientists put bowel cancer under the microscope
Researchers from London's Kingston University have begun a two-year study which could help prolong the lives of people with colorectal tumours.
Help at hand for people with schizophrenia
How can healthy people who hear voices help schizophrenics? Finding the answer for this is at the centre of research conducted at the University of Bergen.