For the first time, researchers are able to observe how specialized cells remove inactive neurons and clean the nervous system.
Understanding how the brain works is essential to unlocking the secrets behind aging and recovering from various neurological disorders. With that in mind, researchers at the Yale School of Medicine studied the interactions between neurons and captured how the brain eliminates them when they stop functioning.
The research, published in the scientific journal Science Advances, shows that if dead cells are not removed, they can become toxins that damage the nervous system. “If you were to stop collecting garbage in New York City, you wouldn’t be able to get in. There would be debris everywhere. The brain, just like New York City, requires efficient garbage disposal,” said Dr. Eyiyemisi Damisah, lead author of the article and assistant professor of neurosurgery at Yale School of Medicine, in a note.
One of the challenges of capturing the moment when this occurs is the speed with which this removal takes place. In addition, many cells die during growth and development in the brain every day.
However, the team developed a photochemical method to induce a single cell death in the brain of live mice. The technique, called “2Phatal”, uses fluorescent markers to highlight how cells communicate and remove dead neurons in real-time. “This is the first time the process has ever been seen in a live mammalian brain,” said Jaime Grutzendler, co-author of the study. “Rather than hitting the brain with a hammer and causing thousands of deaths, inducing a single cell to die allows us to study what is happening right after the cells start to die and watch the many other cells involved [in removing it].”
Watch the video recorded by the scientists that shows the process taking place:
The authors revealed that microglia, astrocytes, and NG2 cells work in a highly coordinated manner to remove dead cells and debris. Each of them has a different function and share the cleaning work.
The researchers also noted that brain cells took at least twice as long to perform this cleaning on an aged brain. This observation can have important implications for the functional decline of the brain. “Cell death is very common in diseases of the brain,” said Damisah. “And understanding the process might yield insights on how to address cell death in an injured brain from head trauma to stroke and other conditions.”