Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists map key brain-to-spinal cord nerve connections for voluntary movement

02.05.2018

Study opens way to explore potential therapies for spinal cord injury and stroke

Researchers trying to help people suffering from paralysis after a spinal cord injury or stroke mapped critical brain-to-spinal cord nerve connections that drive voluntary movement in forelimbs, a development that scientists say allows them to start looking for specific repair strategies.


This microscopic image shows corticospinal neurons and synaptic connections to the spinal cord in a mouse. Spinal interneurons (blue) show synaptic connections (in green) with corticospinal axons (red). Researchers report in Cell Reports the mapping of critical nerve connections to the spine that drive voluntary movement in forelimbs. The gridlines allow scientists to plot the neuron locations along the spinal cord. Scientists say the information will be useful as they begin searching in future preclinical studies for specific repair strategies to help people who had a stroke or spinal cord injury.

Credit: Cincinnati Children's

The study by Yutaka Yoshida, PhD, and colleagues at Cincinnati Children's Hospital Medical Center is an important step toward rehabilitating motor circuits to help motor function recover after an injury or disease damages the central nervous system, the scientists report in Cell Reports.

"The map described in this study should allow us to explore which corticospinal-spinal interneuron connections are good targets for repair and restoration of voluntary movement," says Yoshida, lead investigator in the Division of Developmental Biology. "More research is necessary before human therapies are possible, but this information is very helpful for future repair strategies. We now know which circuits need to be repaired."

The scientists said it will take years for additional investigative work to make the current findings therapeutically relevant. Yoshida and colleagues are conducting new studies to build on the basic neuronal architecture identified in the current study. They want to reach a point where these circuits can be reconstructed to stimulate the recovery of motor function central nervous system injuries.

Corticospinal Schematics

Little has been known about how the corticospinal network of nerve connections between the brain and spinal cord are organized and function together. Seemingly simple tasks like reaching or grabbing require precise coordination between sensory and motor information transmitted through these coordinated connections, according to the researchers.

To map this connectivity in the current study, the scientists study these circuits in laboratory mice--taking advantage of similar corticospinal connections in primates, cats, and rodents.

Working initially from previous studies by his research team and others, Yoshida and colleagues were able to track corticospinal connections from the brain's cerebral cortex near the top of the head down to the spinal cord. They also traced the organization and function of corticospinal circuits using mouse genetics, and a viral tracer (a de-armed rabies virus) that allowed investigators to highlight and capture images of these links.

The connections trace down through what's called the brain's internal capsule, then arrive at the caudal medulla of the brain just above the spinal cord. From there they enter the spinal cord, crisscrossing deep inside the spine as they continue to protrude downward and make additional connections.

Yoshida said his team was able to develop a map of corticospinal neurons that control forelimb and sensory nerve impulses. They also identified specific neurons that control different skilled movements.

In these areas, the scientists show how the nerve fibers connect onto certain premotor interneurons and transmit impulses between neurons to trigger skilled movements. This includes nerve fibers that express a transcription factor called Chx10 (a regulator gene that instructs other genes to turn on or off to initiate biological functions).

Chx10 is linked to nervous system function in other parts of the body, including the eyes. When the researchers silenced Chx10 only in the cervical spinal cord, it hampered the animals' ability to reach for food.

The Importance of Sensing

The researchers also highlighted the connections of corticospinal neurons in the forelimb sensory cortex--which control the animals' ability to sense and convert external stimuli into electrical impulses. They said that in contrast to corticospinal neurons in the motor cortex that directly trigger certain skilled movement, corticospinal neurons in the sensory cortex do not connect directly to premotor neurons. Instead, they connect directly to other spinal interneurons that express a gene called Vglut3.

This is important because when the scientist inhibited neurons expressing Vglut3 in the cervical spinal cord, it also caused deficits in the animals' ability to grab and release food pellets, as well as other goal-oriented tasks.

Key collaborators on this study include scientists at the Precursory Research for Embryonic Science and Technology (PRESTO) at the Japan Science and Technology Agency, the Brain Research Institute at Niigata University in Japan and the University of Cincinnati Medical Center.

###

Funding support for the research came in part from: the National Institute of Neurological Disorders and Stroke (NS093002) PRESTO (JST-JPMJPR13M8), the Japan Society for the Promotion of Science (JSPS) Grants-in-Aid for Scientific Research (KAKENHI 17H04985, 17H05556, 17K19443); a JSPS Postdoctoral Fellowships for Research Abroad, the Foundation for the Promotion of Medical Science, Kato Memorial Bioscience Foundation, Grant-in-Aid from the Tokyo Biochemical Research Foundation, and Japan Heart Foundation Research Grant (MU).

Nick Miller | EurekAlert!

More articles from Health and Medicine:

nachricht Researchers find new potential approach to type 2 diabetes treatment
11.11.2019 | Weill Cornell Medicine

nachricht Why beta-blockers cause skin inflammation
07.11.2019 | Rheinische Friedrich-Wilhelms-Universität Bonn

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Magnets for the second dimension

If you've ever tried to put several really strong, small cube magnets right next to each other on a magnetic board, you'll know that you just can't do it. What happens is that the magnets always arrange themselves in a column sticking out vertically from the magnetic board. Moreover, it's almost impossible to join several rows of these magnets together to form a flat surface. That's because magnets are dipolar. Equal poles repel each other, with the north pole of one magnet always attaching itself to the south pole of another and vice versa. This explains why they form a column with all the magnets aligned the same way.

Now, scientists at ETH Zurich have managed to create magnetic building blocks in the shape of cubes that - for the first time ever - can be joined together to...

Im Focus: A new quantum data classification protocol brings us nearer to a future 'quantum internet'

The algorithm represents a first step in the automated learning of quantum information networks

Quantum-based communication and computation technologies promise unprecedented applications, such as unconditionally secure communications, ultra-precise...

Im Focus: Distorted Atoms

In two experiments performed at the free-electron laser FLASH in Hamburg a cooperation led by physicists from the Heidelberg Max Planck Institute for Nuclear physics (MPIK) demonstrated strongly-driven nonlinear interaction of ultrashort extreme-ultraviolet (XUV) laser pulses with atoms and ions. The powerful excitation of an electron pair in helium was found to compete with the ultrafast decay, which temporarily may even lead to population inversion. Resonant transitions in doubly charged neon ions were shifted in energy, and observed by XUV-XUV pump-probe transient absorption spectroscopy.

An international team led by physicists from the MPIK reports on new results for efficient two-electron excitations in helium driven by strong and ultrashort...

Im Focus: A Memory Effect at Single-Atom Level

An international research group has observed new quantum properties on an artificial giant atom and has now published its results in the high-ranking journal Nature Physics. The quantum system under investigation apparently has a memory - a new finding that could be used to build a quantum computer.

The research group, consisting of German, Swedish and Indian scientists, has investigated an artificial quantum system and found new properties.

Im Focus: Shedding new light on the charging of lithium-ion batteries

Exposing cathodes to light decreases charge time by a factor of two in lithium-ion batteries.

Researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory have reported a new mechanism to speed up the charging of lithium-ion...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

High entropy alloys for hot turbines and tireless metal-forming presses

05.11.2019 | Event News

Smart lasers open up new applications and are the “tool of choice” in digitalization

30.10.2019 | Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

 
Latest News

Magnets for the second dimension

12.11.2019 | Machine Engineering

New efficiency world record for organic solar modules

12.11.2019 | Power and Electrical Engineering

Non-volatile control of magnetic anisotropy through change of electric polarization

12.11.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>