What happens when you die? So far, knowledge about this has mainly come from near-death experiences. Now, a chance discovery offers new insights.
It’s a question that worries many people: What does death feel like? Do we see a light at the end of a tunnel, our own dying body, or does life pass before our inner eyes once more? Some people report this after a near-death experience.
A US study now suggests that at the moment of death, our brains actually trigger memories. At least that’s what brain waves recorded in a dying patient in a hospital suggest.
The fact that this brain activity was recorded at all is due to a coincidence: the treating physicians performed several electroencephalograms (EEG) on the 87-year-old, who had undergone head surgery after a fall and was suffering from epileptic seizures. An EEG records the electrical activity of the brain. During such a recording, the patient suffered a heart attack and died.
According to the scientists in the journal Frontiers in Aging Neuroscience, a total of 15 minutes of brain activity was recorded when the man died. “We focused on what happened in the 30 seconds before and after cardiac arrest,” explains study leader Ajmal Zemmar, a neurosurgeon at the University of Louisville. “Just before and after the heart stopped beating, we saw changes in a specific frequency range of neuronal oscillations, called gamma oscillations, but also in others like delta, theta, alpha, and beta oscillations.”
These brainwaves map patterns of rhythmic neuronal activity. Different waves are associated with diverse functions, with the frequency patterns described in the study being similar to those seen when meditating or recalling memories. This suggests, Zemmar speculates, that shortly before death the brain may play back last memories of important life events by generating such oscillations, “similar to near-death experiences”.
Frank Erbguth, medical director of the Nuremberg University Clinic for Neurology, is not surprised by the observations: “It is nothing new that the human brain creates its own world of images in certain situations.” This is known, for example, from migraine patients, but also from drug users. “Accordingly, near-death experiences are one of a number of very different phenomena in which the brain produces images,” says the President of the German Brain Foundation.
What happens in the brain is easy to explain. With death, the carbon dioxide content in the cells increases: “This leads to a change in the brain electricity and brain metabolism – near-death experiences are located on these two keyboards.” Such could also be experienced by people who are particularly good at meditating.
In these, EEGs showed increased gamma spectra – similar to those reported in the study, says Erbguth: “And we know that these gamma activities indicate that memories are retrieved.” At the same time, gamma waves are very fast, they oscillate at a rate of 30 Hertz per minute. “The gamma band cannot be seen in a conventional EEG,” says the neurologist. Therefore, the differentiated evaluation of the wave ranges undertaken in the study is a new aspect.
Another study back in 2013 showed similar results, except that these changes in gamma waves occurred in rats. The authors of the current study point to this as a possibility that the brain carries out a biological response when dying, which could be the same in all species. However, their study is based on a single patient whose brain was injured and who had also suffered epileptic seizures: “Such epileptic activities mean that the brain electronics are really shaken up,” notes Erbguth. It is difficult to draw conclusions from this about the normal dying brain.
Overall, the study provides another facet of knowledge about the dying brain, which is already comprehensive: if the blood circulation stops, the brain stops communicating between the nerve cells, certain rhythms of the brain’s electrical system shift, and the cells have an electrical one again Output.
As early as 2018, German and US neurologists described in the journal “Annals of Neurology” that this happens in the form of a spreading discharge wave. Erbguth explains the attention that such studies regularly receive by promising to take a look behind the curtain of death: “But everything we look at takes place in front of the curtain.” Even people with near-death experiences are said to be death was just near.
Nonetheless, the current study for neurosurgeon Zemmar offers hope for loved ones: “What we can learn from this research is that even when our loved ones have their eyes closed and are ready to settle down, their brains may be replaying some of the most beautiful moments from what they have experienced.”
Neurologist Erbguth put it more soberly: “Our brain is at least able to produce images again.” Near-death reports showed that it was legitimate to assume this ability for the actually dying brain. However, studies from resuscitation medicine found that while two-thirds of people who had a near-death experience saw pleasant images, one-third reported bad scenes. “I would be satisfied if the transition to death was accompanied by beautiful experiences,” says Erbguth. “But I’m afraid that’s not in your hands.”
