Spinal cord cells surprise researchers: “I hope this will lead to a lot of new ideas and studies”

We all have a unique walk. Your friend does not walk the way you do. This is because the body is capable of performing thousands of tiny movements, and therefore, we will always walk differently.

When we move, the brain sends a signal to the body via the spinal cord. And previously, the scientists believed that the cells in the spinal cord – which are the ones responsible for movement – behaved just like all the other cells in the body.

But that is not the case. This is the conclusion of new research from the University of Copenhagen.

“We have learned that the spinal cord cells do not behave the way we expected. And this explains a lot of the things we have so far been unable to explain, e.g. the fact that we walk differently,” says Associate Professor Rune W. Berg from the Department of Neuroscience at the University of Copenhagen, who is one of the researchers behind the new study.

He and his colleagues have discovered that the cells instead signal to each other in a kind of circle, a so-called alternation or interaction between cells.

“I hope this will lead to a lot of new ideas and studies. The area has been stuck for a long time with the old notion of how the spinal cord cells move. Hopefully, this will make a lot of things fall into place,” he says. But even though Rune W. Berg takes an optimistic view of the future and knowledge of the spinal cord, he stresses that fully repairing damage to the spinal cord is difficult.

“If you have a vase and it breaks into a thousand pieces, you will know what has happened, but you still cannot make it right again. We may be in a similar situation here. We know how the system works, and we know what has happened, but we cannot fully mend it.”

Spinal cord research based on conjecture

Researching the movement of the spinal cord is difficult because we are always moving and using the spinal cord. Therefore, scientists previously believed that the movement of the spinal cord is similar to the movement of the muscles.

“But it is radically different from what we used to believe. There is very little data and research in this area, and that is what makes spinal cord research different. There has been a lot of guesswork and conjecture, and scientists assumed that the spinal cord worked just like the muscles,” Rune W. Berg explains.

If you have a vase and it breaks into a thousand pieces, you will know what has happened, but you still cannot make it right again. We may be in a similar situation here. We know how the system works, and we know what has happened, but we cannot fully mend it.

The researchers have studied the movements of the spinal cord in tortoises, mice and rats, because it was not possible to study it in humans. But according to Rune W. Berg, the same results will apply to humans.

“The principles of how the spinal cord works are the same for vertebrates and humans. The human organism did not develop a new set of principles that are fundamentally different from the ones you find in other animals.”

Can help restore movements

The constant small movements and adjustments of the human body are interrupted if we e.g. suffer a stroke. Here the new knowledge may also prove useful. Because with the right knowledge, we may be able to restore these movements.

“Detailed insight into the production of movement signals may prove crucial. If e.g. these signals are interrupted by a small stroke, which disconnect different brain regions from the spinal cord, therapy may not require sophisticated measures, but instead consist simply of stimulating a specific electrode at the right time,” Rune W. Berg explains. 

The brain uses electric stimulation to tell the body to move. And in fact, doctors are already using electric stimulation of the spinal cord; they just do not know exactly how and why it works, and this is one of the areas that Rune W. Berg’s research may be able to shed light on.

“We know that the quality of life of people who suffer spinal cord injury is significantly reduced if they are subsequently unable to grasp objects or move freely. Knowledge of the nervous system and how the various elements are connected should give us a better basis for mitigation,” Rune W. Berg concludes.

The study, “Movement is governed by rotational neural dynamics in spinal motor networks”, has been published in Nature and is available here.

Contact

Associate Professor Rune W. Berg
+45 26 97 73 94
runeb@sund.ku.dk

Journalist and Press Officer Sascha Kael Rasmussen
+45 93 56 51 68
sascha.kael.rasmussen@sund.ku.dk