A bunch of nerve cells within the mind shows a exceptional potential to halt all types of motion, as revealed by a latest examine performed on mice. This discovering contributes considerably to our understanding of how the nervous system workout routines management over our actions.
When a looking canine detects the scents of a deer, it typically fully freezes. This phenomenon may also be noticed in people who should focus intently on a posh activity.
Now, a latest discovery contributes to our understanding of what occurs within the mind after we abruptly cease shifting.
“We have found a group of nerve cells in the midbrain which, when stimulated, stop all movement. Not just walking; all forms of motor activity. They even make the mice stop breathing or breathe more slowly, and the heart rate slows down,” explains Professor Ole Kiehn, who’s a co-author of the examine.
“There are various ways to stop movement. What is so special about these nerve cells is that once activated they cause the movement to be paused or freeze. Just like setting a film on pause. The actors’ movement suddenly stops on the spot,” says Ole Kiehn.
When the researchers ended activating the nerve cells, the mice would begin the motion precisely the place it stopped. Just like when urgent “play” once more.
“This ‘pause-and-play pattern’ is very unique; it is unlike anything we have seen before. It does not resemble other forms of movement or motor arrest we or other researchers have studied. There, the movement does not necessarily start where it stopped, but may start over with a new pattern,” says Ph.D. Haizea Goñi-Erro, who’s first creator of the examine.
The nerve cells stimulated by the researchers are discovered within the midbrain in an space known as the pedunculopontine nucleus (PPN), they usually differ from different nerve cells thereby expressing a particular molecular marker known as Chx10. The PPN is frequent to all vertebrates including humans. So even though the study was performed in mice, the researchers expect the phenomenon to apply to humans too.
Not related to fear
Some might suggest that the nerve cells are activated by fear. Most people are familiar with the phenomenon of “freezing” caused by extreme fear. But that is not the case.
“We have compared this type of motor arrest to motor arrest or freezing caused by fear, and they are not identical. We are very sure that the movement arrest observe here is not related to fear. Instead, we believe it has something to do with attention or alertness, which is seen in certain situations,” says Assistant Professor Roberto Leiras, who is co-author of the study.
The researchers believe it is an expression of a focused attention. However, they stress that the study has not revealed if this is indeed the case. It is something that requires more research to demonstrate.
May be able to understand Parkinson’s symptoms
The new study may be able to help us understand some of the mechanisms of Parkinson’s disease.
“Motor arrest or slow movement is one of the cardinal symptoms of Parkinson’s disease. We speculate that these special nerve cells in PPN are over-activated in Parkinson’s disease. That would inhibit movement. Therefore, the study, which primarily has focused on the fundamental mechanisms that control movement in the nervous system, may eventually help us to understand the cause of some of the motor symptoms in Parkinson’s disease,” Ole Kiehn concludes.
Reference: “Pedunculopontine Chx10+ neurons control global motor arrest in mice” by Haizea Goñi-Erro, Raghavendra Selvan, Roberto Leiras and Ole Kiehn, 27 July 2023, Nature Neuroscience.
The study was funded by the Novo Nordisk Foundation, the Lundbeck Foundation, and the Swedish Research Council.