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Recent News and Articles on the Keywords: newborn neurons + newborn + neurons  Related to the article below (Last Update: 7/1/2008)

Adult Stem Cells Reprogrammed In Their Natural Environment Science Daily (press release) - Under normal conditions, the majority of newborn cells differentiated into neurons. When he introduced the Ascl1, which had previously been shown to be ... Photo by Einat Adar ScienceBlogs - Jun 6, 2008 He and his colleagues showed that the survival of newborn neurons in the forebrain of the adult zebra finch (Taeniopygia guttata) was significantly affected ... Stem cells show promise in treating fatal children?s disease Fresh News, India - Jun 7, 2008 Myelin coats long sections, known as axons, of brain cells called neurons, without which electrical signalling between neurons becomes sluggish and muddied, ... First stem cell trials might start in OC OCRegister, CA - Jun 25, 2008 Affecting fewer than 1000 infants per year in the United States, the genetic disease causes motor neurons to degenerate, leaving the baby unable to control ... How the Mind Works: Revelations The New York Review of Books - Jun 5, 2008 The brain is of course tremendously complex: a bundle of some hundred billion neurons, or nerve cells, each sharing as many as ten thousand connections with ... Investigating the complexity of respiratory patterns during the ... 7thSpace Interactive (press release), NY - Jun 20, 2008 ... exhibit lower complexity, suggesting that a synchronized homogeneous group of neurons in the central respiratory network are active during these events. ... Human Stem Cells Show Promise Against Fatal Children's Diseases Science Daily (press release) - Jun 4, 2008 Myelin coats long sections, known as axons, of brain cells called neurons, and without it, the electrical signaling between neurons becomes sluggish and ... Respiratory Control in Neonatal Rats Exposed to Prenatal Cigarette ... RedOrbit, TX - Jun 3, 2008 Point: medullary pacemaker neurons are essential for both eupnea and gasping in mammals vs. medullary pacemaker neurons are essential for gasping, ... Stem Cells Stop Mouse Shivers Cold, Could Thwart Rare ... Scientific American - Jun 5, 2008 The problems are caused by disruptions in nerve cell (neuron), communication triggered by a lack of myelin, which, in normal nerve cells, ... Natus Medical raises FY and Q2 revenue guidance SmallCapInvestor - Jun 5, 2008 Neuron diagnostic and newborn care products manufacturer Natus Medical Inc. (Nasdaq:BABY) this morning raised its full year and second quarter 2008 revenue ...BABY

Newborn Neurons Like to Hang with the In-Crowd

Like any new kid on the block that tries to fit in, newborn brain cells need to find their place within the existing network of neurons. The newcomers jump right into the fray and preferentially reach out to mature brain cells that are already well connected within the established circuitry, report scientists at the Salk Institute for Biological Studies in the online edition of Nature Neuroscience.

At first, they gingerly sniff out pre-existing connections between brain cells but as the new neurons mature over time they get emboldened and muscle out the old guys. “Adding new neurons could be a very problematic process if newborn cells would make connections all over the place,” explains Fred H. Gage, Ph.D., a professor in the Gene Expression Laboratory and the Vi and John Adler Chair for Research on Age-Related Neurodegenerative Diseases. “But if they are only replacing already existing connections there is less chance of error,” he adds.

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Top: Newborn neurons send out tiny dendritic protrusions (shown in green) that seek out pre-synaptic areas -- the sending terminals of nerve cells (shown in purple) -- that are already well connected within the established circuitry (shown in red). Middle: Over time, the tip of the dendritic protrusions thickens, strengthening the connection between young and old. Top: As the young neuron matures, it monopolizes the synaptic connection site.

Neurons make contact via specialized structures called synapses. As a signal traveling along a nerve branch arrives at the pre-synaptic area, it releases a chemical signal. The signaling molecules travel across the synapse and induce a signal on the neighboring, receiving nerve fiber or dendrite. A typical neuron sports about 7,000 synapses through which it stays in touch with roughly 1,000 other cells. But just how young neurons make their presence known and hook up with already well-connected elders has been unclear.

“If you have hopes that one day neuronal stem cells can replace damaged neurons in neurodegenerative diseases such as Alzheimer’s or Parkinson’s disease you have to ensure that these cells make proper connections, form functional synapses and integrate into the rest of the brain,” says postdoctoral fellow Nicolas Toni, Ph.D., who headed the current study.

To figure out how the newcomers do it, the Salk researchers injected a virus carrying the gene for green fluorescent protein into the hippocampus, a brain region harboring neural stem cells that give rise to new neurons. Newly born neurons infected with virus were marked by a fluorescent dye enabling the researchers to follow their fate over time as they tried to get accepted into the existing circuitry.

With the help of a whole arsenal of high-tech imaging technology and the electron tomography expertise of Mark. H. Ellisman, Ph.D., a professor at the National Center for Microscopy and Imaging Research at the University of California, San Diego, Toni then zoomed in at a nanometer scale and watched how the young and the old got acquainted.

He observed that between three and four weeks after injection of the virus newborn neurons sent out dendritic filopodia—tiny feelers that probe the environment. “When we analyzed them in three dimensions, the tip of the filopodia was preferentially associated with synapses already connected to other neurons,” explains Toni.

However, as the new neurons matured, the tiny tips filled out and started to monopolize the synaptic connections. “That’s what we believe is the crux of the study: the survival of new neurons may depend on the ability to compete out the older existing neurons,” says Gage. Earlier studies had shown that if young neurons fail to receive signals from other brain cells they wither and die. By connecting to functional synapses, the newborn neurons ensure that they are not reaching out to deadbeats.

The Gage lab previously identified a subunit of the NMDA receptor, a protein complex that transduces signals sent by neighboring cells, as the newborn neurons’ life-saving equipment. The NMDA receptor is activated by the neurotransmitter glutamate, a chemical released by neurons in order to transmit information to neighboring cells. Whenever the receptor picks up a glutamate signal it is stimulated and relays the signal. For young neurons that signal means survival.

As a matter of fact, only about half of all newly born neurons manage to successfully integrate into the existing network of brain cells, at least in mice living in bare standard cages. Providing the mice with a stimulating, enriched environment—large cages filled with running wheels, colored tunnels and playmates—boost the number of neurons that manage to hook up with the existing network to 80 percent, reinforcing the observation that using one’s brain cells is the best way to optimize brain function throughout one’s lifetime.

Also contributing to the study where postdoctoral researchers E. Matthew Teng, Ph.D., James B. Aimone, Ph.D., Chunmei Zhao, Ph.D., Antonella Consiglio, Ph.D., staff scientist Henriette van Praag, Ph.D., all at the Salk Institute, and postdoctoral fellows Eric A. Bushong , Maryann E. Martone, Ph.D., and Mark H. Ellisman at the National Center for Microscopy and Imaging Research at the University of California, San Diego.

The Salk Institute for Biological Studies in La Jolla, California is an independent nonprofit organization dedicated to fundamental discoveries in the life sciences, the improvement of human health, and the training of future generations of researchers. Jonas Salk, M.D., whose polio vaccine all but eradicated the crippling disease poliomyelitis in 1955, opened the Institute in 1965 with a gift of land from the City of San Diego and the financial support of the March of Dimes.

What is ALS

Amyotrophic lateral sclerosis (ALS), often referred to as "Lou Gehrig's disease," is a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. Motor neurons reach from the brain to the spinal cord and from the spinal cord to the muscles throughout the body. The progressive degeneration of the motor neurons in ALS eventually lead to their death. When the motor neurons die, the ability of the brain to initiate and control muscle movement is lost. With voluntary muscle action progressively affected, patients in the later stages of the disease may become totally paralyzed. Yet, through it all, for the vast majority of people, their minds remain unaffected.

A-myo-trophic comes from the Greek language. "A" means no or negative. "Myo" refers to muscle, and "Trophic" means nourishment---"No muscle nourishment." When a muscle has no nourishment, it "atrophies" or wastes away. "Lateral" identifies the areas in a person's spinal cord where portions of the nerve cells that signal and control the muscles are located. As this area degenerates it leads to scarring or hardening ("sclerosis") in the region.

As motor neurons degenerate, they can no longer send impulses to the muscle fibers that normally result in muscle movement. Early symptoms of ALS often include increasing muscle weakness, especially involving the arms and legs, speech, swallowing or breathing. When muscles no longer receive the messages from the motor neurons that they require to function, the muscles begin to atrophy (become smaller). Limbs begin to look "thinner" as muscle tissue atrophies.

Although the cause of ALS is not completely understood, the recent years have brought a wealth of new scientific understanding regarding the physiology of this disease.

While there is not a cure or treatment today that halts or reverses ALS, there is one FDA approved drug, Rilutek®, that modestly slows the progression of ALS as well as several other drugs in clinical trials that hold promise.

Importantly, there are significant devise and therapies that can manage the symptoms of ALS that help people maintain as much independence as possible and prolong survival.  It is important to remember that ALS is a quite variable disease; no two people will have the same journey or experiences.  There are medically documented cases of people in whom ALS ‘burns out,’ stops progressing or progresses at a very slow rate.  No matter what your individual course or situation may be, The ALS Association and your medical team are here to help.

To learn more about the personal stories of people who are living fully, click here. As one man put it, “I’ve made ALS part of my life, not my whole life.”