(Press-News.org) Contact information: Paula Byron
pbyron@vt.edu
540-526-2027
Virginia Tech
Researchers discover how retinal neurons claim the best brain connections
Discovery may shed light on brain disease, development of regenerative therapies
Real estate agents emphasize location, location, and – once more for good measure – location. It's the same in a developing brain, where billions of neurons vie for premium property to make connections. Neurons that stake out early claims often land the best value, even if they don't develop the property until later.
Scientists at the Virginia Tech Carilion Research Institute and the University of Louisville have discovered that during neurodevelopment, neurons from the brain's cerebral cortex extend axons to the edge of the part of the brain dedicated to processing visual signals – but then stop. Instead of immediately making connections, the cortical neurons wait for two weeks while neurons from the retina connect to the brain.
Now, in a study to be published in the Nov. 14 issue of the journal Cell Reports, the scientists have discovered how. The retinal neurons stop their cortical cousins from grabbing prime real estate by controlling the abundance of a protein called aggrecan.
Understanding how aggrecan controls the formation of brain circuits could help scientists understand how to repair the injured brain or spinal cord after injury or disease.
"Usually when neuroscientists talk about repairing injured brains, they're thinking about putting neurons, axons, and synapses back in the right place," said Michael Fox, an associate professor at the Virginia Tech Carilion Research Institute and lead author of the study. "It may be that the most important synapses – the ones that drive excitation – need to get there first. By stalling out the other neurons, they can get the best spots. This study shows that when we think about repairing damaged neural networks, we need to consider more than just where connections need to be made. We also need to think about the timing of reinnervation."
The researchers genetically removed the retinal neurons, which allowed the cortical axons to move into the brain earlier than they normally would.
"We were interested in what environmental molecular cues allow the retinal neurons to control the growth of cortical neurons," said Fox, who is also an associate professor of biological sciences in Virginia Tech's College of Science. "After years of screening potential mechanisms, we found aggrecan."
Aggrecan is a protein that has been well studied in cartilage, bones, and the spinal cord, where it is abundant after injuries. According to Fox, aggrecan may be able to isolate damaged areas of the spinal cord to stop inflammation and prevent further destruction. The downside, however, is that aggrecan inhibits axonal growth, which prevents further repair from taking place.
"Axons see this environment and either stop growing or turn around and grow in the opposite direction," said Fox.
Although it is less studied in the developing brain, aggrecan appears in abundance there. In the new study, the researchers found that retinal neurons control aggrecan in a region that receives ascending signals from retinal cells as well as descending signals from the cerebral cortex.
Once the retinal neurons have made connections, they cause the release of enzymes that break down the aggrecan, allowing cortical neurons to move in.
Fox said it is interesting that the retinal axons can grow in this region of the developing brain, despite the high levels of aggrecan. He suspects that it may be because retinal neurons express a receptor – integrin – that cortical axons do not express.
###
The study, "A molecular mechanism regulating the timing of corticogeniculate innervation," is by Fox, Jianmin Su, a research assistant professor, and Carl Levy, an undergraduate from Suffolk, Va., all with the Virginia Tech Carilion Research Institute; graduate student Justin Brooks and undergraduate Jessica Wang from Virginia Commonwealth University; and Tania Seabrook, a postdoctoral associate, and William Guido, a professor and the chair of the Department of Anatomical Sciences and Neurobiology, both with the University of Louisville School of Medicine.
Written by Ken Kingery
Researchers discover how retinal neurons claim the best brain connections
Discovery may shed light on brain disease, development of regenerative therapies
2013-10-31
ELSE PRESS RELEASES FROM THIS DATE:
Simple plants aren't always easy: Revision of the liverwort Radula buccinifera complex
2013-10-31
Simple plants aren't always easy: Revision of the liverwort Radula buccinifera complex
The supposedly widespread and variable Australasian liverwort species Radula buccinifera is nothing of the kind. The species was described in 1844, and reported for New Zealand in 1855. ...
Danish research provides new knowledge about the body's fight against HIV
2013-10-31
Danish research provides new knowledge about the body's fight against HIV
When a person is infected with HIV the virus infects the cells of the immune system. From here the virus spreads around the body, while at the same time breaking down important ...
Patient in 'vegetative state' not just aware, but paying attention
2013-10-31
Patient in 'vegetative state' not just aware, but paying attention
Research raises possibility of devices in the future to help some patients in a vegetative state interact with the outside world
A patient in a seemingly vegetative state, unable to move or ...
Defective nanotubes turned into light emitters
2013-10-31
Defective nanotubes turned into light emitters
UPV/EHU-University of the Basque Country researchers have developed and patented a new source of light emitter based on boron nitride nanotubes and suitable for developing high-efficiency optoelectronic devices
This news ...
Scent marking
2013-10-31
Scent marking
The mammalian equivalent of showy plumage
Many animals use scent marking to advertise their territory – they urinate at strategic locations – to communicate their social status and ownership. It has ...
Research identifies ways to improve access to mental health services
2013-10-31
Research identifies ways to improve access to mental health services
A study by researchers from the Universities of Liverpool and Manchester has identified ways to improve how older people and ethnic minority populations access mental health care services.
As ...
Studies of experimental hepatitis C drug show promise for preventing recurrence in liver transplant
2013-10-31
Studies of experimental hepatitis C drug show promise for preventing recurrence in liver transplant
DETROIT – New drug therapies offer promise to some hepatitis C sufferers whose transplanted livers are threated by a recurrence of the disease, including some ...
Scientists discover why newborns get sick so often
2013-10-31
Scientists discover why newborns get sick so often
New research published in the Journal of Leukocyte Biology suggests that newborns lack the toll-like receptor 3 (TLR3) which recognizes different viruses and mediates immune response ...
Studies: Current hepatitis C treatments can't be used by more than half of patients; others lose opportunity for treatment
2013-10-31
Studies: Current hepatitis C treatments can't be used by more than half of patients; others lose opportunity for treatment
DETROIT – More than half of chronic hepatitis C patients studied in a new research project led by Henry Ford Hospital were not treated ...
HIV antibody infusions show promise for treating SHIV-infected monkeys
2013-10-31
HIV antibody infusions show promise for treating SHIV-infected monkeys
NIH-supported scientists advocate trying similar strategy in people
WHAT:
Two teams are reporting results from experiments in which they infused powerful ...
LAST 30 PRESS RELEASES:
Exercise as an anti-ageing intervention to avoid detrimental impact of mental fatigue
UMass Amherst Nursing Professor Emerita honored as ‘Living Legend’
New guidelines aim to improve cystic fibrosis screening
Picky eaters by day, buffet by night: Butterfly, moth diets sync to plant aromas
Pennington Biomedical’s Dr. Leanne Redman honored with the E. V. McCollum Award from the American Society for Nutrition
CCNY physicists uncover electronic interactions mediated via spin waves
Researchers’ 3D-printing formula may transform future of foam
Nurture more important than nature for robotic hand
Drug-delivering aptamers target leukemia stem cells for one-two knockout punch
New study finds that over 95% of sponsored influencer posts on Twitter were not disclosed
New sea grant report helps great lakes fish farmers navigate aquaculture regulations
Strain “trick” improves perovskite solar cells’ efficiency
How GPS helps older drivers stay on the roads
Estrogen and progesterone stimulate the body to make opioids
Dancing with the cells – how acoustically levitating a diamond led to a breakthrough in biotech automation
Machine learning helps construct an evolutionary timeline of bacteria
Cellular regulator of mRNA vaccine revealed... offering new therapeutic options
Animal behavioral diversity at risk in the face of declining biodiversity
Finding their way: GPS ignites independence in older adult drivers
Antibiotic resistance among key bacterial species plateaus over time
‘Some insects are declining but what’s happening to the other 99%?’
Powerful new software platform could reshape biomedical research by making data analysis more accessible
Revealing capillaries and cells in living organs with ultrasound
American College of Physicians awards $260,000 in grants to address equity challenges in obesity care
Researchers from MARE ULisboa discover that the European catfish, an invasive species in Portugal, has a prolonged breeding season, enhancing its invasive potential
Rakesh K. Jain, PhD, FAACR, honored with the 2025 AACR Award for Lifetime Achievement in Cancer Research
Solar cells made of moon dust could power future space exploration
Deporting immigrants may further shrink the health care workforce
Border region emergency medical services in migrant emergency care
Resident physician intentions regarding unionization
[Press-News.org] Researchers discover how retinal neurons claim the best brain connectionsDiscovery may shed light on brain disease, development of regenerative therapies