(Press-News.org) COLLEGE PARK, Md - A discovery by a University of Maryland-led research team offers hope for treating "lazy eye" and other serious visual problems that are usually permanent unless they are corrected in early childhood.
Amblyopia afflicts about three percent of the population, and is a widespread cause of vision loss in children. It occurs when both eyes are structurally normal, but mismatched – either misaligned, or differently focused, or unequally receptive to visual stimuli because of an obstruction such as a cataract in one eye.
During the so-called "critical period" when a young child's brain is adapting very quickly to new experiences, the brain builds a powerful neural network connecting the stronger eye to the visual cortex. But the weaker eye gets less stimulation and develops fewer synapses, or points of connection between neurons. Over time the brain learns to ignore the weaker eye. Mild forms of amblyopia such as "lazy eye" result in problems with depth perception. In the most severe form, deprivation amblyopia, a cataract blocks light and starves the eye of visual experiences, significantly altering synaptic development and seriously impairing vision.
Because brain plasticity declines rapidly with age, early diagnosis and treatment of amblyopia is vital, said neuroscientist Elizabeth M. Quinlan, an associate professor of biology at UMD. If the underlying cause of amblyopia is resolved early enough, the child's vision can recover to normal levels. But if the treatment comes after the end of the critical period and the loss of synaptic plasticity, the brain cannot relearn to see with the weaker eye.
"If a child is born with a cataract and it is not removed very early in life, very little can be done to improve vision," Quinlan said. "The severe amblyopia that results is the most difficult to treat. For that reason, science has the most to gain by a better understanding of the underlying mechanisms."
Quinlan, who specializes in studying how communication through the brain's circuits changes over the course of a lifetime, wanted to find out what process controls the timing of the critical period of synaptic plasticity. If researchers could find the neurological on-off switch for the critical period, she reasoned, clinicians could use the information to successfully treat older children and adults.
Researchers in Quinlan's University of Maryland lab teamed up with their counterparts in the laboratory of Alfredo Kirkwood at Johns Hopkins University to address two questions: What are the age boundaries of the critical period for synaptic plasticity, when it comes to determining eye dominance? And what developmental processes are involved?
Experiments in rodents suggested the timing of the critical period is controlled by a specific class of inhibitory neurons, which come into play after a visual stimulus activates excitatory neurons that link the eye to the visual cortex. The inhibitory neurons act as signal controllers, affecting the interactions between excitatory neurons and synapses.
"The generally accepted view has been that as the inhibitory neurons develop, synaptic plasticity declines, which was thought to occur at about five weeks of age in rodents," roughly equivalent to five years of age in humans, Quinlan said. But in earlier experiments, Quinlan and Kirkwood found no correlation between the development of these inhibitory neurons and the loss of plasticity. In fact, they found the visual circuitry in rodents was highly adaptable at ages beyond five weeks.
In their latest research the UMD-led team looked "one synapse upstream from these inhibitory neurons," Quinlan said, studying the control of that synapse by a protein called NARP (Neuronal Activity-Regulated Pentraxin). Working with two sets of mice – one group genetically similar to wild mice and another that lacked the NARP gene - the researchers covered one eye in each animal to simulate conditions that produce amblyopia.
The mice that were genetically similar to wild mice developed amblyopia, with characteristic dominance of the normal eye over the deprived eye. But the mice that lacked NARP did not develop amblyopia, regardless of age or the length of time one eye was deprived of stimulation.
The study, published in the current issue of the peer-reviewed journal Neuron, demonstrated that only one specific class of synapses was affected by the absence of NARP. Without NARP, the mice simply had no critical period in which the brain circuitry was weakened in response to the impaired blocking vision in one eye, Quinlan said. Except for the lack of this plasticity, their vision was normal.
"It's remarkable how specific the deficit is," Quinlan said. Without the NARP protein, "these animals develop normal vision. Their brain circuitry just isn't plastic. We can completely turn off the critical period for plasticity by knocking out this protein."
Since there are indications that NARP levels vary with age, the discovery raises hope that a treatment targeting NARP levels in humans could allow correction of amblyopia late in life, without affecting other aspects of vision.
INFORMATION:
Media contacts:
Heather Dewar, hdewar@umd.edu, 301-405-9267
Elizabeth M. Quinlan, equinlan@umd.edu, 301-405-7396
Yu Gu, Shiyong Huang, Michael G. Chang, Paul Worley, Alfredo Kirkwood, and Elizabeth M. Quinlan, "Obligatory Role for the Immediate Early Gene NARP in Critical Period Plasticity," Neuron 79, 335-346, July 24, 2013
An original photo illustration is available for news media use at http://cmns.umd.edu/news-events/features/1159
Re-learning how to see
Researchers find a crucial on-off switch in visual development
2013-08-02
ELSE PRESS RELEASES FROM THIS DATE:
August 2013 story tips from Oak Ridge National Laboratory
2013-08-02
ENERGY – Green battery . . .
By substituting lignin for highly engineered, expensive graphite to make battery electrodes, researchers have developed a process that requires fewer steps and offers better performance. Renewable Electrodes from Wood Products, or ReNEW-PRO, is a low-cost lithium-ion battery anode made inexpensively from lignin, a renewable resource and byproduct of the pulp and paper industry. ReNEW-PRO was developed in collaboration with GrafTech International Holdings. The ORNL team was led by Orlando Rios of the Materials Science and Technology Division. ...
Blocking key enzyme in cancer cells could lead to new therapy
2013-08-02
Researchers from the University of Illinois at Chicago College of Medicine have identified a characteristic unique to cancer cells in an animal model of cancer -- and they believe it could be exploited as a target to develop new treatment strategies.
An enzyme that metabolizes the glucose needed for tumor growth is found in high concentrations in cancer cells, but in very few normal adult tissues. Deleting the gene for the enzyme stopped the growth of cancer in laboratory mice, with no associated adverse effects, reports Nissim Hay, UIC professor of biochemistry and molecular ...
Las Cumbres Observatory 'Sinistro' astronomy imager captures first light
2013-08-02
Las Cumbres Observatory Global Telescope (LCOGT), with first lights at nine new 1-meter telescopes since April of 2012, achieved another critical milestone by capturing the first on-sky image with a production Sinistro camera. In development for over six years, the camera is arguably more important than the telescopes that will use them. "A telescope is really nothing more than a large camera lens," explained Joe Tufts, instrumentation scientist on the Sinistro project. "A large, precise, stable, and very expensive camera lens."
Sinistro is the primary science camera ...
Novel drug shuts down master protein key to lymphoma
2013-08-02
NEW YORK (August 1, 2013) -- Researchers have discovered how an experimental drug is capable of completely eradicating human lymphoma in mice after just five doses. The study, led by researchers at Weill Cornell Medical College, sets the stage for testing the drug in clinical trials of diffuse large B-cell lymphoma (DLBCL), the most common subtype of non-Hodgkin lymphoma, itself the seventh most frequently diagnosed cancer in the U.S.
In the journal Cell Reports, published today online, the scientists describe how the powerful master regulatory transcription factor Bcl6 ...
Speedier scans reveal new distinctions in resting and active brain
2013-08-02
A boost in the speed of brain scans is unveiling new insights into how brain regions work with each other in cooperative groups called networks.
Scientists at Washington University School of Medicine in St. Louis and the Institute of Technology and Advanced Biomedical Imaging at the University of Chieti, Italy, used the quicker scans to track brain activity in volunteers at rest and while they watched a movie.
"Brain activity occurs in waves that repeat as slowly as once every 10 seconds or as rapidly as once every 50 milliseconds," said senior researcher Maurizio Corbetta, ...
Genetics: More than merely a mutated gene
2013-08-02
EAST LANSING, Mich. — If two women have the same genetic mutation that puts them at higher-than-average risk for a disease such as breast cancer, why does only one develop the disease?
In the current issue of PLOS Genetics, Michigan State University genetic scientists have begun to understand how the rest of the genome interacts with such mutations to cause the differences we see among individuals.
"It's been known for a while that genetic mutations can modify each other's effects," said Ian Dworkin, MSU associate professor of zoology and co-author of the paper. "And ...
Burnt sugar derivative reduces muscle wasting in fly and mouse muscular dystrophy
2013-08-02
A trace substance in caramelized sugar, when purified and given in appropriate doses, improves muscle regeneration in a mouse model of Duchenne muscular dystrophy. The findings are published today, Aug. 1, in the journal Skeletal Muscle.
Morayma Reyes, professor of pathology and laboratory medicine, and Hannele Ruohola-Baker, professor of biochemistry and associate director of the Institute for Stem Cell and Regenerative Medicine, headed the University of Washington team that made the discovery. The first authors of the paper were Nicholas Ieronimakis,UW Department of ...
Obesity doesn't reduce chance of getting pregnant with donor eggs
2013-08-01
In women who use donor eggs to become pregnant through in vitro fertilization (IVF), those who are obese are just as likely to become pregnant as normal weight women, according to a new report.
Studies have shown that obesity is associated with lower chances of pregnancy using IVF, but most of this work is limited to women using their own eggs. Research on outcomes for obese women using donor eggs has had mixed results.
The new analysis by investigators at Washington University School of Medicine in St. Louis and the University of California-Los Angeles pooled and analyzed ...
Breath analysis reliably indicates presence, level of infection in mice, UCI study finds
2013-08-01
Irvine, Calif., July 31, 2013 — Breath analysis may prove to be an accurate, noninvasive way to quickly determine the severity of bacterial and other infections, according to a UC Irvine study appearing online today in the open-access journal PLOS ONE.
Employing a chemical analysis method developed for air pollution testing, UC Irvine microbiologists and chemists were able to correlate inflammation levels in laboratory mice to the amount of naturally produced carbon monoxide and other gases in breath samples.
The findings point to human applications of this technology ...
New target identified for food allergy therapy
2013-08-01
DENVER - Researchers at National Jewish Health have identified an enzyme that is essential to the allergic reaction to peanuts. Blocking the enzyme's activity in sensitized mice prevented diarrhea and inflammation, and reduced levels of several proteins associated with allergies. The findings, published online in the Journal of Allergy and Clinical Immunology, identify the enzyme, known as Cyp11a1, as a potential target for treatment of increasingly common and potentially deadly food allergy.
"Right now, we have no therapy for food allergy other than to avoid the allergenic ...
LAST 30 PRESS RELEASES:
MSU team develops scalable climate solutions for agricultural carbon markets
Playing an instrument may protect against cognitive aging
UNM study finds link between Grand Canyon landslide and Meteor Crater impact
Ultra-hot Jupiter’s death spiral could reveal stellar secrets
You only get one brain! The best helmet material for protecting your noggin
Neurodegeneration and stroke after GLP-1RAs in diabetes and obesity
Pediatric COVID-19 hospitalization trends by race and ethnicity, 2020-2023
Research spotlight: New genetic roadmap offers insights into obesity and diabetes
Fred Hutch leads new Vanguard Study for Cancer Screening Research Network
‘Mismatched’ transplants now safe, effective for blood cancer patients, study finds
New research helps narrow down uncertainties in near-term precipitation projections for the Asian Water Tower
AI tool accurately detects tumor location on breast MRI
Researchers use OCT imaging to uncover how the fallopian tube transports embryos
PolyU secures RGC theme-based research scheme funding to develop cost-effective and sustainable Co-GenAI model
Van Andel Institute scientists develop technique for high-resolution single cell epigenetic analysis
The Lundquist Institute wins multi-year NIH grant exceeding $11 million to transform diagnosis and treatment of deadly mucormycosis
Review suggests ending adult boosters for tetanus, diphtheria
ESMT Berlin welcomes Rebecca Schaumberg to faculty
Blocking a little-known protein may offer new hope for devastating lung disease
Medieval medicine was smarter than you think – and weirdly similar to TikTok trends
FAU receives NIH grant to investigate amphetamine addiction
Realizing on-site carbon nanotube photo-thermoelectric imaging
Most of us love memes. But are they a form of comics?
Novel biosensor allows real-time monitoring of sucrose uptake in plants
Korea University researchers reveal revealing how WEE1 drives cancer resistance to immunotherapy
Pusan National University researchers develop breakthrough deep learning model that enhances handheld 3D medical imaging
SLAS Discovery and SLAS Technology demonstrate research impact with 2024 impact factors
Disease-causing bacteria can deal with stink as long as they get a meal
Mapping the metabolism of blood stem cells
UK air quality improved since 2015 but targets still missed
[Press-News.org] Re-learning how to seeResearchers find a crucial on-off switch in visual development