Stimulating the Brain Post-Death

"[By medical standards] this is not a living brain. But it is a cellularly active brain."
"Cell death in the brain occurs across a longer time window than we previously thought. We are showing that … [it's] a gradual, stepwise process [and that in some cases, the cell death processes can be postponed or even reversed]."
"[The brain of a large mammal] retains a previously underappreciated capacity for restoration [of circulation and certain cellular activities hours after death]."
Nenad Sestan, Yale School of Medicine

"Previously, we have only been able to study cells in the large mammalian brain under static or largely two-dimensional conditions utilizing small tissue samples outside of their native environment." 
"For the first time, we are able to investigate the large brain in three dimensions, which increases our ability to study complex cellular interactions and connectivity."
Stefano G. Daniele, M.D./Ph.D. candidate

A network of neural connections in the brain

"Restoration of consciousness was never a goal of this research."
"The researchers were prepared to intervene with the use of anesthetics and temperature-reduction to stop organized global electrical activity if it were to emerge. Everyone agreed in advance that experiments involving revived global activity couldn't go forward without clear ethical standards and institutional oversight mechanisms."
Stephen Latham, director, Yale's Interdisciplinary Center for Bioethics

Scientists have developed a system called BrainEx that preserved and even restored brain cell activity in pigs' brains after death. Above, images of brain cells with neurons shown in green, astrocytes (a type of support cell in the brain) in red, and cell nuclei in blue. After death, neurons and astrocytes undergo cellular disintegration without any treatment (left), but if brains are placed in the BrainEx system, these cells are salvaged (right).

Credit: Stefano G. Daniele & Zvonimir Vrselja; Sestan Laboratory; Yale School of Medicine

Scientists have succeeded in the restoration of a level of activity in the brains of pigs slaughtered hours before, the work revealing a degree of resilience among cells in a brain that has been separated from its biologically natural supply of blood and oxygen to keep it actively engaged. Their finding has raised the anticipation that medical advances could proceed from there with further studies, at the same time raising issues relating to the definition of death.

The results were reported in the journal Nature. Research of this value could conceivably lead to new therapies to counter stroke and other similar conditions. Outcomes of further research building on this one could provide a new system in the study of the brain and clarify how drugs function within the brain -- according to the researchers -- though they also stated there were no current plans in the works to use the technique on human brains.

The study realized financing for the most part by the National Institutes of Health. The 32 pigs' brains used for the research were sourced at a local slaughterhouse from pigs that were killed for human consumption. The brains were placed in an apparatus in the research laboratory four hours after slaughter. There, a device the researchers had created which they called BrainEx -- a machine seated outside the organ that pumps a blood-like fluid they had created into the brain at body temperature -- was used.

Once the brains had been flooded with the liquid for a period of six hours, activity of some molecules, cells and synapses were restored and it appeared to the scientists that cell death appeared to have been attenuated. These were surprising and notable effects that lasted for up to ten hours post-mortem. Though there was no large-scale electrical activity that would indicate awareness, the results were extremely useful for there was no intention to restore consciousness, an outcome the scientists wanted in fact to avoid.

This research had the purpose of exploring whether certain functions might be restored long after death occurred. In one area of the brain, individual brain cells had succeeded in maintaining key details of their structure. Cells from untreated brains indicated severe degradation, in comparison. When the neurons were removed by the scientists from the treated brains and underwent electrical stimulation, viability was demonstrated in the cells' response.

Evidence was found by researchers that brain cells had absorbed blood sugar and oxygen, producing carbon dioxide, a signal of functionality, when the artificial blood was studied both before entering the treated brains and once it emerged. Blood vessels in treated brains responded to a drug whose function is to expand vessels. According to Dr. Sestan, researchers have no idea whether normal whole brain function could be restored.

The scientists, should consciousness have been evident in the experiments, would have responded by using anesthesia and low temperatures to halt the process, ending the experiment, according to Yale ethicist Stephen Latham -- the study co-author -- reflecting the lack of ethical consensus in performing such research with a conscious brain.

Microcosm diagram of the mind by Robert Fludd.

"This research reminds us that ‘death’ is less an event, and more of a process that occurs over time. Cells within the human organism may be alive for some period of time after the human person has died." 
"At present we should be clear that this research does not have any implications for brain death or for organ transplantation. Nor does it mean that there is a realistic prospect, any time soon, of bringing back people from the dead."
'Brain death' refers to the irreversible loss of the capacity for awareness and consciousness. Once someone has been diagnosed as ‘brain dead’ there is currently no way for that person to ever recover. The human person that they were, has gone."
Dominic Wilkinson, professor of medical ethics, University of Oxford

Scientists have revived the brain cells of dead pigs in a study that experts say calls into question our understanding of what makes an animal alive. Getty Images