Zombies … let’s hope we never face one. However, the phenomenon exists in less dramatic facets. A scientific study helped determine this. It happens to some cells in the human brain. A few hours after death, they can become more active in surprising ways. They are the brain’s zombie genes.
Scientists identified these changes post mortem. This was thanks to the analysis of gene expression in brain tissues. They found that the activity of certain types of brain cells varied over time.
‘We decided to do a sham death experiment that looked at the expression of all human genes. It was carried out at time intervals from 0 to 24 hours. We took a large block of recently collected brain tissue that was left at room temperature. This is how we replicate an autopsy », explained Dr. Jeffrey Loeb. He is the director of neurology at the Chicago School of Medicine at the University of Illinois.
The scientists observed glial cells in these tissues that were voluntarily obtained during brain surgery. These were enlarged after death, though they didn’t think it was too surprising. These are inflammatory and their job is to clean the areas where brain injuries occur due to lack of oxygen or after a stroke. “Most studies assume that everything in the brain stops when the heart stops beating. But that’s not the case, ”said Loeb.
The experiment divided the analyzed genes into groups. And so it was found that around 80% of the genes remained relatively stable for 24 hours. These include the so-called housekeeping genes, which support basic brain functions. There is another group of genes related to the activities of the brain (memory, thinking). These deteriorated rapidly in the hours after death.
The third group consists of the so-called zombie genes of the brain. They were characterized by an increase in their activity after death, while other neuronal genes decreased at the same time. In this way, the pattern of changes changes post mortem it peaked about 12 hours.
“Researchers need to take these genetic and cellular changes into account. The interval should be shortened post mortem as much as possible to reduce the extent of these changes. We now know which genes and cell types are stable. Some also worsen and some increase over time. The results of brain studies post mortem They can be better understood, ”concluded Loeb.