• sciandenvironment

What happens to our brain when we die?

First brain recording of a human being brings evidence of how our brain reacts during death and can be linked to near-death experiences.

By Margaux Chekroun

Photo courtesy of geralt from Unsplash.

What happens when we die? What does our brain do? How does it feel? Do we see our life flashing before our eyes? A recent study published in the journal, Frontiers in Aging Neuroscience, recorded the brain activity of an 87-year-old epileptic man using continuous electroencephalography (EEG) when the patient underwent cardiac arrest, due to traumatic subdural hematoma, and passed away. This is the first recording of a dying brain in a human being in non-experimental, real-life conditions but still within a clinical setting. It provides an insight into neuronal activity during death. The study gives evidence that the brain can produce coordinated activity in the near-death period. A near-death experience represents a personal state of mind associated with clinical death or preceding death. People undergoing near-death experiences usually encounter a short period of clinical death, where their heart rate, breathing and reflexes stop for a period of time, and are finally brought back to life, usually through medical reanimation. Neuroscientists often consider near-death experiences to be linked to an alteration of consciousness induced by disturbance in the cerebral biochemistry balance due to death or psychological response triggered by the death threat. However, this new study shakes this theory of subjective near-death experience, as interesting brain wave patterns provide new details on what might be going on in the brain when we die.

Reported symptoms of near-death experiences differ for each individual but usually include an awareness of being dead; a sense of peace; seeing ‘flashbacks’ or ‘life flashing before one’s eyes’; an out-of-body experience; or a sense of moving (usually through a ‘tunnel’).

Reported symptoms of near-death experiences differ for each individual but usually include an awareness of being dead; a sense of peace; seeing ‘flashbacks’ or ‘life flashing before one’s eyes’; an out-of-body experience; or a sense of moving (usually through a ‘tunnel’). These symptoms are perceived on a scientific point of view as subjective alterations of consciousness due to brain chemistry imbalance during death. This new study shows that these symptoms might not be as subjective as we previously thought they were. Indeed, the article explains that an accidental death occurred while recording the brain activity of an epileptic patient. The organiser of the study, neurosurgeon Dr Ajmal Zemmar stated, “Our study is the first ever to show that these oscillatory waves are present in the dying human brain, which may provide a neurophysiological substance, a brain signal form, for what we call near-death experiences.” Brain activity was found even after the heart rate stopped. The patient’s brain activity recordings were focused on the 30 seconds before cardiac arrest where there was an increase in oscillatory activity and high levels of gamma oscillations. The rhythmic pattern then decreased after the heart rate stopped for approximately 30 seconds, before finally stopping. In healthy subjects, gamma oscillations are part of cognitive functions associated with memory recall, information processing, attention, dreaming and can be amplified while meditating. These brain oscillations could explain the near-death-experience symptoms such as life flashbacks, as this research implies that people dying might experience memory recall and dream-like state just before brain activity finally ceases.

However, this study needs to be assessed cautiously before generalising the findings to all patients. Limitations that occurred in this typical case might have influenced the brain activity recorded. First of all, there is only one example of this precise type of brain recording during death on human beings. We would need more similar studies to be able to compare and confirm a general effect happening on the dying brain. Secondly, the patient underwent a traumatic brain injury, including seizure, haemorrhage and swelling, all of which can influence a patient’s rhythmic brain activity. Thirdly, significant doses of anticonvulsant drugs were administered to the patient which, similarly, can have an effect on neuronal network activity.

All those factors make the interpretation of the data even more complicated as they also affect rhythmic brain pattern recordings. Nevertheless, it was noted in the study that the brain oscillations recorded were still significantly important, as similar patterns were also found in highly controlled experimental studies on rodents. It was also highlighted that recording brain activity during death on human beings would always be complicated as inherently, the patients studied cannot be healthy if they are close to death, and the factors linked to their health issues leading to death will always have an influence on the brain activity.

In the end, we now have a more defined idea of what happens to our brain and in our minds when we die. It is suggested that the final brain activity recorded during death - gamma waves is linked to memory recall and gives an explanation for the symptoms reported during near death experiences, or the so-called ‘life flashing before one’s eyes.’ Future research will focus on acquiring new and similar case studies recording brain activity during death in human beings, but also trying to determine where exactly those brain waves occurred to give more sense and precision to this data. In the near future, we might have a more specific idea of what our brain undergoes during death, which ultimately could lead us to a better understanding of our consciousness and of death itself, which in science and in general is one of the most mysterious processes to this day.