Some brain cells are known to remain alive for some time after a person's heart stops. In a new study published in Scientific Reports, scientists have shown that the activity of some of them even increases during days.
What scientists did
Scientists from the University of Illinois examined fresh brain tissue from people who had been removed during epilepsy surgery. During such operations, parts of the brain that are responsible for the onset of an attack are removed.
In the experiment, scientists left brain tissue samples at room temperature for up to 24 hours. During this time, they periodically checked the activity of the cells of these tissues and their genes.
What the scientists found
Scientists compared the activity of different types of genes. The first group is the «household» genes, which are responsible for the basic functions of cells. They are interesting in that their activity (expression), in contrast to the activity of other genes, is almost the same in all body tissues. After brain death, their expression remained at a constant level for the entire 24 hours.
The second group of genes is “neuronal”. They are expressed in neurons and are responsible for providing basic brain functions (memory, thinking). After 12 hours, their activity began to decline.
The third group of genes in the press release of the study, scientists conventionally called «zombie genes.» She was responsible for the work of neuroglia — auxiliary cells of the nervous system. The activity of these genes increased after «death» within 24 hours of observation. The expression enhancement pattern peaked at 12 hours. At the same time, against the background of neuronal degeneration, glial cells increased in size, they had new processes.
It became known how long after death a person is really dead< /span>
After doctors record the death of a person, his heart may show signs of life. However, this does not give hope that it will clog again.
Read article
“The fact that glial cells increase after death is not a very big surprise, given that they have an anti-inflammatory function and they should clean up the brain after damage that occurs, for example, with a lack of oxygen and a stroke,» said Jeffrey Loeb, professor at the University of Illinois, co-author of the study.
Why scientists need to know this
The data obtained by scientists is not just curious information. These results should influence the methodology of brain research.
“Most studies assume that all brain processes stop when the heart stops beating, but this is not the case. Our data is needed to interpret studies on human brain tissue. Previously, quantitative indicators of post-mortem changes have not been studied, ”explained Loub.