[BLOG POST] Brain Plasticity: How Adult Born Neurons Get Wired – Neuroscience News

FEBRUARY 3, 2017

Summary: Researchers report adult neurogenesis not only helps increase the number of cells in a neural network, it also promotes plasticity in the existing network. Additionally, they have identified the role the Bax gene plays in synaptic pruning.

Source: University of Alabama at Birmingham.

One goal in neurobiology is to understand how the flow of electrical signals through brain circuits gives rise to perception, action, thought, learning and memories.

Linda Overstreet-Wadiche, Ph.D., and Jacques Wadiche, Ph.D., both associate professors in the University of Alabama at Birmingham Department of Neurobiology, have published their latest contribution in this effort, focused on a part of the brain that helps form memories — the dentate gyrus of the hippocampus.

The dentate gyrus is one of just two areas in the brain where new neurons are continuously formed in adults. When a new granule cell neuron is made in the dentate gyrus, it needs to get ‘wired in,’ by forming synapses, or connections, in order to contribute to circuit function. Dentate granule cells are part of a circuit that receive electrical signals from the entorhinal cortex, a cortical brain region that processes sensory and spatial input from other areas of the brain. By combining this sensory and spatial information, the dentate gyrus can generate a unique memory of an experience.

Overstreet-Wadiche and UAB colleagues posed a basic question: Since the number of neurons in the dentate gyrus increases by neurogenesis while the number of neurons in the cortex remains the same, does the brain create additional synapses from the cortical neurons to the new granule cells, or do some cortical neurons transfer their connections from mature granule cells to the new granule cells?

Their answer, garnered through a series of electrophysiology, dendritic spine density and immunohistochemistry experiments with mice that were genetically altered to produce either more new neurons or kill off newborn neurons, supports the second model — some of the cortical neurons transfer their connections from mature granule cells to the new granule cells.

This opens the door to look at how this redistribution of synapses between the old and new neurons helps the dentate gyrus function. And it opens up tantalizing questions. Does this redistribution disrupt existing memories? How does this redistribution relate to the beneficial effects of exercise, which is a natural way to increase neurogenesis?

“Over the last 10 years there has been evidence supporting a redistribution of synapses between old and new neurons, possibly by a competitive process that the new cells tend to ‘win,’” Overstreet-Wadiche said. “Our findings are important because they directly demonstrate that, in order for new cells to win connections, the old cells lose connections. So, the process of adult neurogenesis not only adds new cells to the network, it promotes plasticity of the existing network.”

The study opens the door to look at how this redistribution of synapses between the old and new neurons helps the dentate gyrus function. NeuroscienceNews.com image is for illustrative purposes only.

[TED Talk] Sandrine Thuret: You can grow new brain cells. Here’s how

Can we, as adults, grow new neurons? Neuroscientist Sandrine Thuret says that we can, and she offers research and practical advice on how we can help our brains better perform neurogenesis—improving mood, increasing memory formation and preventing the decline associated with aging along the way.

[WEB SITE] Scientists discover neuron-producing stem cells in the membranes covering the brain

Credit: Heidi Cartwright, Wellcome Images

 

Discovery brings with it possible implications for brain regeneration –

In a cross-domain study directed by professor Peter Carmeliet (VIB – KU Leuven), researchers discovered unexpected cells in the protective membranes that enclose the brain, the so called meninges. These ‘neural progenitors’ (stem cells that differentiate into different kinds of neurons) are produced during embryonic development.

See Also: Stem cells in the brain: Limited self-renewal

These findings show that the neural progenitors found in the meninges produce new neurons after birth, highlighting the importance of meningeal tissue as well as these cells’ potential in the development of new therapies for brain damage or neurodegeneration. A paper highlighting the results is published in the journal Cell Stem Cell.

Scientists’ understanding of brain plasticity, or the ability of the brain to grow, develop, recover from injuries and adapt to changing conditions throughout our lives, has been greatly broadened in recent years. Before the discoveries of the last few decades, neurologists once thought that the brain became ‘static’ after childhood. This dogma has changed, with researchers finding more and more evidence that the brain is capable of healing and regenerating in adulthood, thanks to the presence of stem cells. However, neuronal stem cells were generally believed to only reside within the brain tissue, not in the membranes surrounding it.

The meninges: unappreciated no more

Believed in the past to serve a mainly protective function to dampen mechanical shocks, the meninges have been historically underappreciated by science as having neurological importance in its own right. The data gathered by the team challenges the current idea that neural precursors—or stem cells that give rise to neurons—can only be found inside actual brain tissue.

Learn More: Scientists sniff out unexpected role for stem cells in the brain

Prof. Peter Carmeliet notes: “The neuronal stems cells that we discovered inside the meninges differentiate to full neurons, electrically-active and functionally integrated into the neuronal circuit. To show that the stem cells reside in the meninges, we used the extremely powerful single-cell RNA sequencing technique, a very novel top-notch technique, capable of identifying the [complex gene expression signature] nature of individual cells in a previously unsurpassed manner, a première at VIB.”

Following up on future research avenues

When it comes to future leads for this discovery, the scientists also see possibilities for translation into clinical application, though future work is required.

“An intriguing question is whether these neuronal stem cells in the meninges could lead to better therapies for brain damage or neurodegeneration. However, answering this question would require a better understanding of the molecular mechanisms that regulate the differentiation of these stem cells,” says Carmeliet. “How are these meningeal stem cells activated to become different kinds of neurons? Can we therapeutically ‘hijack’ their regeneration potential to restore dying neurons in, for example, Alzheimer’ Disease, Parkinson’s Disease, amyotrophic lateral sclerosis (ALS), and other neurodegenerative disorders? Also, can we isolate these neurogenic progenitors from the meninges at birth and use them for later transplantation? These findings open up very exciting research opportunities for the future.”

Moving into unchartered territory is high risk, and can offer high gain, but securing funding for such type of research is challenging. However, Carmeliet’s discoveries were made possible to a large extent by funding through “Opening the Future: pioneering without boundaries”, a recently created Mecenas Funding Campaign for funding of high risk brain research but with potential for breakthrough discoveries, started up by the KU Leuven in 2013 and unique in Flanders.

Read Next: A better way to grow motor neurons from stem cells

“Being able to use such non-conventional funding channels is of utmost importance to break new boundaries in research,” says Carmeliet. “This unique Mecenas funding initiative by the KU Leuven is innovative and boundary-breaking by itself. Our entire team is enormously grateful for the opportunities it has created for our investigations”.

Note: Material may have been edited for length and content. For further information, please contact the cited source.

VIB – Flanders Institute for Biotechnology   press release

Publication

Bifari F et al. Neurogenic Radial Glia-like Cells in Meninges Migrate and Differentiate into Functionally Integrated Neurons in the Neonatal Cortex.   Cell Stem Cell, Published Online November 23 2016. doi: 10.1016/j.stem.2016.10.020

Similar Stories On …

• stem cells
• cortex
• brain development
• plasticity
• neurogenesis

Source: Scientists discover neuron-producing stem cells in the membranes covering the brain

[WEB SITE] This Nifty Infographic Is a Great Introduction to Neuroplasticity and Cognitive Therapy

It’s startling to think about how we’ve got a spaceship billions of miles away rendezvousing with Pluto, yet here on Earth there are major aspects of our own anatomy that we’re almost completely ignorant about. We’ve climbed Everest, sent men to the moon, and invented the Internet — but we still don’t know how our brains work. The positive outlook is that many health, science, and research specialists believe we’re on the precipice of some major neuroscientific breakthroughs.

One example of a recent discovery with major implications is our further understanding of neuroplasticity. Simply put, we used to think our brain was what it was — unchangeable, unalterable. We were stuck with what nature gave us. In actuality, our brains are like plastic. We can alter neurochemistry to change beliefs, thoughts processes, emotions, etc. You are the architect of your brain. You also have the power to act against dangerous impulses such as addiction. The therapeutic possibilities here are endless.

Below, broken up into two parts, is a terrific infographic detailing the essence of what we know about neuroplasticity and how it works. It was created by the folks at Alta Mira, a San Francisco-area rehabilitation and recovery center.

Source: This Nifty Infographic Is a Great Introduction to Neuroplasticity and Cognitive Therapy | Big Think

[WEB SITE] UT Southwestern researchers find potential mechanism to prevent epileptic seizures following TBI.

UT Southwestern Medical Center researchers have found that halting production of new neurons in the brain following traumatic brain injury can help reduce resulting epileptic seizures, cognitive decline, and impaired memory.

Injury to the brain stimulates the production of new neurons, but these new cells are sometimes hyperexcitable, disrupting neural circuits and causing recurring seizures, researchers with UT Southwestern’s Texas Institute for Brain Injury and Repair reported in Nature Communications.

Effectively stopping the process in genetically modified mice resulted in fewer seizures. In addition, eliminating the development of new neurons – a process called neurogenesis ? appeared to reduce cognitive decline and impairment of memory, common effects of seizures.

“Understanding the mechanisms that promote aberrant neurogenesis caused by traumatic brain injury and subsequent seizures may open new therapeutic avenues to prevent epilepsy and associated memory problems caused by impact,” said senior author Dr. Jenny Hsieh, Associate Professor of Molecular Biology and a member of the UT Southwestern Hamon Center for Regenerative Science and Medicine.

Halting development of new neurons resulted in a roughly 40 percent reduction in seizure frequency in the mice, but did not alter the duration of individual seizures. However, the researchers found that stopping neurogenesis before the development of seizures had a long-lasting effect, suppressing chronic seizure frequency for nearly one year, even at a late stage of the disease.

An estimated 3 million Americans and 65 million people worldwide currently live with epilepsy, costing an estimated $15.5 billion annually, according to the Centers for Disease Control and Prevention. Traumatic brain injury accounts for 20 percent of epileptic seizures, but how or why recurring seizures develop after a severe brain injury has thus far been unclear. Some drugs can help control seizures, but there is no drug to prevent or cure epilepsy.

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Degenerative diseases of the heart, brain, and other tissues represent the largest cause of death and disability in the world, affecting virtually everyone over the age of 40 and accounting for the lion’s share of health care costs. Regenerative medicine represents a new frontier in science, which seeks to understand the mechanistic basis of tissue aging, repair, and regeneration and to leverage this knowledge to improve human health.

UT Southwestern’s Hamon Center for Regenerative Science and Medicine, led by Molecular Biology Chair Dr. Eric Olson, was established in 2014 with a $10 million endowment gift from the Hamon Charitable Foundation. The Center’s goals are to understand the basic mechanisms underlying tissue and organ formation, and then to use this knowledge to regenerate, repair, and replace tissues damaged by aging and injury.

The Hsieh lab studies the cellular and molecular mechanisms of neurogenesis to understand how stem cells become mature, functioning nerve cells, and how aberrant neurogenesis contributes to seizure formation, an unwarranted side effect of neuroregenerative strategies.

Source: UT Southwestern researchers find potential mechanism to prevent epileptic seizures following TBI

[TED Talk] Sandrine Thuret: You can grow new brain cells. Here’s how

Until recently, it was believed that adult brains simply didn’t grow new brain cells — what we developed as children was all we got. But now we know our brains can grow new nerve cells, in a process called neurogenesis, throughout our entire lives. Neuroscientist Sandrine Thuret studies how we do that, and offers research and practical advice on how we can help our brains grow — and why we should.

[Infographic] Rewiring the brain

Rewiring the brain (infographic) | evangelos.katsioulis.com.

[ARTICLE] New Directions in Research and Therapies in Traumatic Brain Injury – Full Text HTML/PDF

Abstract:

Traumatic brain injury (TBI) is a significant cause of disability and death and its incidence is rising in some specific populations. TBI can result in various disabilities, cognitive problems and psychiatric disorders, depending on the location of the injury and premorbid patient conditions.

Effective pharmacological and surgical treatments, however, are currently limited. Most randomised clinical trials for TBI treatments carried out to date have failed to show significant benefits. Initiatives such as the TRACK-TBI have highlighted the large variability in TBI treatment quality at different hospitals and widely differing death rates. This stimulated the establishment of the International Initiative for TBI Research (InTIBR), which aims to improve disease characterisation and patient management.

The development of effective treatments for TBI and their evaluation requires an understanding of the complex neuroregenerative processes that follow an injury. In the case of haematoma in TBI, decompressive craniectomy can be a life-saving intervention but must be performed rapidly. The neurotrophic agent, Cerebrolysin®, acts by mimicking neurotrophic factors (NTFs) and by stimulating the endogenous production of NTF in brain tissue. Experimental models show that this drug increases neurogenesis following TBI but these findings need to be converted into clinical practice. The potential of Cerebrolysin in TBI was demonstrated in a large retrospective cohort trial in Romania (n=7,769 adults). Cerebrolysin significantly improved Glasgow Outcome Scores (GOS) and respiratory distress (RDS) in patients with moderate or severe TBI at 10 and 30 days compared with controls.

This and other experimental treatments have potential in TBI but, in developing such therapies, the design of clinical trials should closely reflect the reality of biological processes underlying natural recovery from brain injury.

Full Text HTML —>  New Directions in Research and Therapies in Traumatic Brain Injury | Touch Neurology | Independent Insight for Medical Specialists.

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[SPECIAL REPORT] Brain Plasticity and Stroke Rehabilitation – Full Text HTML

Abstract

Neuronal connections and cortical maps are continuously remodeled by our experience. Knowledge of the potential capabilityof the brain to compensate for lesions is a prerequisite for optimal stroke rehabilitation strategies.

Experimental focal cortical lesions induce changes in adjacent cortex and in the contralateral hemisphere. Neuroimaging studies in stroke patients indicate altered poststroke activation patterns, which suggest some functional reorganization. To what extent functional imaging data correspond to outcome data needs to be evaluated. Reorganization may be the principle process responsible for recovery of function after stroke, but what are the limits, and to what extent can postischemic intervention facilitate such changes?

Postoperative housing of animals in an enriched environment can significantly enhance functional outcome and can also interact with other interventions, including neocortical grafting. What role will neuronal progenitor cells play in future rehabilitation—stimulated in situ or as neural replacement? And what is the future for blocking neural growth inhibitory factors?

Better knowledge of postischemic molecular and neurophysiological events, and close interaction between basic and applied research, will hopefully enable us to design rehabilitation strategies based on neurobiological principles in a not-too-distant future.

Continue —>  Brain Plasticity and Stroke Rehabilitation.

[VIDEO] Neurogenesis – Grow New Brain Cells With Exercise – YouTube

Back in Medical School we were told that we were given a certain number of brain cells and that was it for life. However, this idea that humans do not grow new brain cells is now fully demonstrated to be wrong. How exciting it is that we possess the ability to re-grow new brain cells, a process called neurogenesis. Not only that, but we retain this ability throughout our entire lifetimes. So you might be wondering: What can I do to increase neurogenesis? In this video we will explore at least one way to make this happen.