Neuroscientists have recorded the activity of a dying human brain and discovered rhythmic brain wave patterns similar to those during dreaming, memory recall, and meditation. A new study suggests an explanation for vivid life recall in near-death experiences. Maryam Clark investigates.
Imagine reliving your entire life in the space of seconds. Like a flash of lightning, you are outside your body, seeing memorable moments of your life. Known as ‘life recall’, it can be similar to a near-death experience. What happens inside your brain during and after death have puzzled neuroscientists for centuries. However, a study published to Frontiers in Aging Neuroscience suggests that your brain may remain active and coordinated during and even after the transition to death, and be programmed to orchestrate the whole process.
When an 87-year-old patient developed epilepsy, Dr Raul Vicente of the University of Tartu, Estonia, and colleagues used continuous electroencephalography (EEG) to detect the seizures and treat the patient. During these recordings, the patient had a heart attack and passed away. This unexpected event allowed the scientists to record the activity of a dying human brain for the first time ever.
“We measured 900 seconds of brain activity around the time of death and set a specific focus to investigate what happened in the 30 seconds before and after the heart stopped beating,” said Dr Ajmal Zemmar, a neurosurgeon at the University of Louisville, US, who organised the study.
“Just before and after the heart stopped working, we saw changes in a specific band of neural oscillations, so-called gamma oscillations, but also in others such as delta, theta, alpha, and beta oscillations.”
Brain oscillations (more commonly known as ‘brain waves’) are patterns of rhythmic brain activity normally present in living human brains. The different types of oscillations, including gamma, are involved in high-cognitive functions, such as concentrating, dreaming, meditation, memory retrieval, information processing, and conscious perception, just like those associated with memory flashbacks.
“Through generating oscillations involved in memory retrieval, the brain may be playing a last recall of important life events just before we die, similar to the ones reported in near-death experiences,” Zemmar speculated. “These findings challenge our understanding of when exactly life ends and generate important subsequent questions, such as those related to the timing of organ donation.”
While this study is the first of its kind to measure live brain activity during the process of dying in humans, similar changes in gamma oscillations have been previously observed in rats kept in controlled environments. This means it is possible that, during death, the brain organises and executes a biological response that could be conserved across species.
These measurements are based on a single case and stem from the brain of a patient who had suffered injury, seizures and swelling, which complicate interpretation of the data. Nonetheless, Zemmar plans to investigate more and sees the results as a source of hope.
“Something we may learn from this research is: although our loved ones have their eyes closed and are ready to leave us to rest, their brains may be replaying some of the nicest moments they experienced in their lives.”
