Washington [US]: Researchers at the University of Illinois at Chicago analysed gene expression in fresh brain tissue and found that gene expression in some cells actually increased after death. In the hours after we die, certain cells in the human brain are still active. Some cells even increase their activity and grow to gargantuan proportions, according to new research from the University of Illinois Chicago.

In a newly published study in the journal Scientific Reports, the UIC researchers analysed gene expression in fresh brain tissue — which was collected during routine brain surgery — at multiple times after removal to simulate the post-mortem interval and death. They found that gene expression in some cells actually increased after death.

These ‘zombie genes’ — those that increased expression after the post-mortem interval – were specific to one type of cell: inflammatory cells called glial cells. The researchers observed that glial cells grow and sprout long arm-like appendages for many hours after death.

Dr. Jeffrey Loeb, head of neurology and rehabilitation at the UIC College of Medicine and corresponding author on the paper, specifies the implications of this discovery, “Most research studies that use postmortem human brain tissues to find treatments and potential cures for disorders such as autism, schizophrenia and Alzheimer’s disease, do not account for the post-mortem gene expression or cell activity. Most studies assume that everything in the brain stops when the heart stops beating, but this is not so.”

“Our findings will be needed to interpret research on human brain tissues. We just haven’t quantified these changes until now.”