For example, even after his heart had stopped, brain waves were still measured and it could just be that dying people really see the highlights of their lives pass by.

When neurosurgeon Ajmal Zemmar has the electrodes placed on the head of his 87-year-old patient with epilepsy, he has no way of knowing that this patient will posthumously play a leading role in his next research paper that will deal with brain activity in a dying brain. The elderly epilepsy patient in question has been hospitalized after a fall and Zemmar and his team are doing everything they can to help him. Using the electrodes, his brain activity is continuously measured and epileptic seizures can be detected and treated. But despite the good care of the doctors, the man is deteriorating visibly, only to die of a heart attack – yet unexpectedly and with the electrodes still on the skull.

Unique

It is a tragic event, under unique circumstances. Because while this man is dying, his brain activity is continuously measured. And with that, the unexpected tragedy allows doctors to study what goes on in a dying brain. Their findings are in the magazine this week Frontiers in Aging Neuroscience and remarkable in several respects.

The research

In the study, the doctors and researchers focus on the brain activity measured in the last 30 seconds before the heart stopped and the 30 seconds after that. “Just before the heart stopped working, we saw changes in brain waves with a specific frequency, called gamma waves,” explains lead author Zemmar. Scientias.nl from. “These are high-frequency brainwaves associated with higher cognitive functions in everyday life, such as retrieving memories, meditating and concentrating. When we do that sort of thing, we see the gamma waves increase.” And remarkably, the researchers saw a similar increase in gamma waves shortly before the 87-year-old patient’s heart stopped beating. “And not just from gamma waves,” emphasizes Zemmar. “Also from brain waves with a different frequency, such as delta, theta, alpha and beta waves. But the increase in gamma waves was the most striking.”

Although some reserve in the interpretation of the changes in brain activity is in order, Zemmar and colleagues dare to speculate somewhat about what the brain was doing so shortly before the onset of death. “What we see is that shortly before and after the heart has stopped, the gamma waves follow the same pattern as in healthy people reminiscing or dreaming. And while we can’t say for sure what the brain of the dying patient was doing, if we put all the data side-by-side – it certainly doesn’t seem inconceivable that the brain played back the important and happy memories and the patient lives his life. so saw it pass by.”

Increase in brain activity after death

What is equally interesting is that the electrodes still detected brain waves even after the patient’s heart had stopped. “That’s very surprising,” says Zemmar. “Because you would think that when the heart stops pumping blood, the brain is dead too. The fact that brain waves were still detected after the heart stopped beating cautiously suggests that brain activity may continue after the heart stops beating,” said Zemmar. But it is much too early to draw conclusions based on these observations about what the brain is still capable of after the heart has stopped. “The data come from only one case and it is not possible at this time to say with certainty that the observed brain activity actually proves that the brain is still functionally active, in the sense that the patient is still dreaming or having flashbacks, ” emphasizes Zemmar.

One case

While the observations are particularly fascinating, Zemmar would like to emphasize that their interpretations are really speculative for now. “It is important to mention again that it is all based on just one case: the brain of one patient. And that patient had brain damage: bleeding and swelling. These may have influenced brain activity, which may make interpreting them even more difficult.”

Previous animal experiments

With this one, special case, the data when it comes to activity in dying human brains is sparse. But that something special can happen in the brain around death has already been suggested on the basis of animal experiments. “In 2013, an experiment was conducted in the US in which scientists caused healthy rats – while the brain activity of the animals was being monitored – to have a heart attack and die,” says Zemmar. And surprisingly, the scientists saw the same changes in gamma waves occurring in the brains of those rats shortly before the heart stopped, as have now been observed in the brain of the 87-year-old man. “That is quite surprising,” says Zemmar. “Because, from an evolutionary point of view, rats and humans are quite far apart.” Interpreting this remarkable similarity between dying rats and humans is again tricky. “But perhaps we are dealing with an ancient biological response that has been conserved throughout species evolution.” In that scenario, you would think that brain activity at the time of death has an important function. But we can only guess at that. “Perhaps the biological response is aimed at calming us – through the retrieval of fond memories – before we die,” speculates Zemmar. “And maybe it’s just a mechanism that’s triggered when we’re about to die and the consequences of which we don’t understand at this point.”

Follow-up research

For now, one case seems to raise more questions than it answers. Still, Zemmar and colleagues felt a strong need to share their observations with the world. “First of all, because the observations raise questions that are not only interesting from a scientific point of view, but also important for society,” says Zemmar. He is thinking, for example, of the observation that brain activity continues some time after the heart has already stopped beating. “As a doctor, that makes you think: because what is the moment when you can declare someone dead and, for example, start organ donation?” In addition, Zemmar hopes that the publication will lead to more of these (coincidentally collected) EEG scans coming to the surface. “We present the very first observations of a dying human brain. Only when we have more such observations can we determine whether what we have seen happening is a universal phenomenon.”

It is clear to Zemmar that those last moments of life also deserve to be examined more closely. Such studies can have important implications for dealing with and caring for dying people and their loved ones. “As a neurosurgeon, I regularly deal with deaths. And I know how hard it is for family members to see their family member, who they sometimes can’t communicate with, is dying. As a doctor, you stand by and fervently wish you could do more. How nice it would be if we could give the family members more insight into what is happening in their loved one’s brain at such a time and tell them – based on further scientific research – that their loved one is calm at that moment, because his or her brain replays the most beautiful memories he or she has acquired during life.”