Updated on 03/30/2022 at 12:55 pm
- What happens when you die? This has been researched for a long time, so far the findings have mostly come from near-death experiences.
- A chance discovery now suggests that our life is flashing by in images once again in its dying breaths.
It’s a question that worries many people: What is death like? Do we see a light at the end of a tunnel, our own dying body, or does life flash before our inner eyes once more? Some people report this after a near-death experience. Results from a US study now suggest that at the time 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 is due to a coincidence: the attending physicians performed several electroencephalograms (EEG) on the 87-year-old man, who had undergone head surgery after a fall and was suffering from epileptic seizures. An EEG records the electrical activity of the brain. During this recording, the patient suffered a heart attack and died.
Observation suggests: Last encounter with important memories
In total, the scientists report in the journal Frontiers in Aging Neuroscience, 15 minutes of brain activity were 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. “Shortly 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 brain waves map patterns of rhythmic neuronal activity. Different waves are associated with different functions, with the frequency patterns described in the study being similar to those observed when meditating or recalling memories. This suggests, speculates Zemmar, that shortly before death the brain can reproduce the last memories of important life events by generating such oscillations, “similar to near-death experiences.”
Not surprising and “easily explainable”
Frank Erbguth, medical director of the Neurology Clinic at the University of Nuremberg, is not surprised by the observations: “It’s not news that the human brain creates its own world of images in certain situations.” This is known, for example, by migraine patients, but also by drug users. “So near-death experiences are one of several 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’s electrical system and brain metabolism – near-death experiences are located on these two keyboards.” This can also be experienced by people who are particularly good at meditating. In these, the 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.” We speak of gamma waves with a frequency of 30 Hertz – that is, 30 oscillations per second. “The gamma band cannot be seen on a conventional EEG,” says the neurologist. Therefore, the differentiated evaluation of the wavebands performed in the study is a new aspect.
Death studies get a lot of attention
Another study in 2013 showed similar results, except that these changes in gamma waves occurred in rats. The authors of the present study point to this as a possibility for the brain to carry out a biological response when dying, which may be the same in all species. However, their study is based on a single patient whose brain was injured and who also had epileptic seizures: “Such epileptic activities mean that the brain’s electricity is really shaken,” notes Erbguth. It’s hard 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 blood circulation stops
- the brain interrupts communication between nerve cells,
- certain rhythms of the brain’s electricity change, the cells have an electrical output again.
As early as 2018, German and American neurologists described in the journal “Annals of Neurology” that this happens in the form of a spreading wave of discharge. Erbguth explains the attention these studies regularly receive by promising to look behind the curtain of death: “But everything we look at happens in front of the curtain.” Even people with near-death experiences were close to death.
Hope for beautiful last moments before death
However, 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 ready to settle down, their brains may be repeating some of the most beautiful moments they experienced.”
Neurologist Erbguth put it more soberly: “Our brain is at least capable of producing images again.” Near-death reports showed that it was legitimate to assume this ability for the really dying brain. However, studies of 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 pleased if the transition to death was accompanied by beautiful experiences,” Erbguth said. “But I’m afraid that’s not in your hands.” (Alice Lanzke, dpa/af)
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Updated on 08/12/2021 at 20:35
Sometimes you wake up drenched in sweat and relieved that it was just a nightmare. Other nights you wish the dream never ended. In both cases the question arises: what does this mean?