Returning from Death: An Examination of the Validity of Near Death Experiences
Usma Sajid | October 29th, 2023
Let’s consider the age-old question: what happens when we die?
Whether we look at this question through a theological lens or a more scientific approach, there is bound to be subjectivity. No one who dies can come back to tell us the tale, can they? Well, there are the people who have come very, very close to death. Is there an answer in these accounts of people who have “died?”
What is NDE?
According to Cognitive Neuroscientist Olaf Blanke from Switzerland, these brushes with death, or near death experiences (NDEs), can be defined as “a set of subjective phenomena, often including an OBE [out of body experience], that are triggered by a life-threatening situation” . Often, these people are patients who have had cardiac arrests, only to survive at the last moment. So the next question is: what is an “out of body experience?” Blanke states that OBEs are defined as “disturbed bodily multisensory integration, primarily in [the] right temporo-parietal cortex” .
NDE x neurobiology
We can evaluate how close these experiences are to what constitutes death through neurobiology. In a paper by psychiatrist Lukas Konopka at Loyola University, he explains how some patients with cardiac issues who had an NDE show damage in both white and gray matter of the brain. Gray matter is essentially where cell bodies and dendrites are, making it the “processing” area, while white matter contains mostly axons which connect signals. Furthermore, during these experiences the brain received decreased oxygen, which could result in hallucinations. Anesthesia can also play a role in near death experiences, specifically, the anesthetic drug ketamine can cause overly positive emotions. More specifically in reference to the temporal lobe, patients who had abnormal electroenchepholgrams (EEG’s) in the temporal lobe reported deep emotions and a sense of “destiny.” OBEs are also associated with this area of the brain. Despite this association, there are patients who have flat-lined on their EEGs and still reported an NDE (Konopka).
One study reported that 50% of those who had an NDE reported that they were aware of being dead, 24% had an OBE, 31% reported going through a tunnel, and 32% reported that they met deceased people. In the study, by Dean Mobbs of Cambridge and Caroline Watt of the University of Edinburgh, they found that many of these phenomena could be artificially produced, such as people with glaucoma, a visual disorder, reporting tunnel vision. They also report a theory that arousal systems in the midbrain could be responsible for NDE’s. The neurotransmitter, norepinephrine, is part of systems that evoke positive emotions and hallucinations (Mobbs and Watt).
Unraveling NDE: A Brainwave Perspective
However, many of these explanations seem to fall short in fully explaining what a near-death experience is. It still seems impossible to empirically decide just how near these are to death. Another study done at the University of Michigan by Gang Xu and colleagues found that out of four dying patients who had ventilatory support withdrawn, two had surges of gamma brain waves which further surged with cardiac arrest. Could cardiac arrest be causing a surge in brain activity that leads to surreal experiences that these patients are then perceiving as “going into a light” or the more vivid recollections? They ultimately concluded from their findings that high frequency activation of temporo-parietal-occipital junctions occurred right before death, which also occurs in awake and dreaming healthy human brains (Xu et al.). This connects with findings from other studies that OBE’s occur in the temporo-parietal cortex.
Based on these findings, it follows that near death experiences share more characteristics with hallucinatory experiences such as OBE’s, rather than give a tangible connection to what death might be like. By further studying near death experiences – like the case studies of cardiac arrest in Michigan – we might be able to provide an answer for not what happens after death, but at least what happens right before it. This information is useful not just to satisfy our curiosity on the afterlife, but could prove useful in better understanding brain death, irreversible comas, and more.
Blanke, Olaf, et al. “Chapter 20 – Leaving Body and Life Behind: Out-of-Body and Near-Death Experience.” The Neurology of Consciousness, Academic Press, 2016, pp. 323-347. ScienceDirect, https://www.sciencedirect.com/science/article/pii/B9780128009482000200.
Konopka, Lukas M. “Near death experience: neuroscience perspective.” Croatian Medical Journal, vol. 56, no. 4, 2015, pp. 392-393, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4576755/#:~:text=When%20the%20brain%20undergoes%20decreased,and%20transcendental%20feelings%20(7).
Mobbs, Dean, and Caroline Watt. “There is nothing paranormal about near-death experiences: how neuroscience can explain seeing bright lights, meeting the dead, or being convinced you are one of them.” Trends in Cognitive Sciences, vol. 15, no. 10, 2011, pp. 447-449. https://www.cell.com/trends/cognitive-sciences/fulltext/S1364-6613(11)00155-0?_returnURL=http://linkinghub.elsevier.com%2Fretrieve%2Fpii%2FS1364661311001550%3Fshowall%3Dtrue&cc=y%3D#articleInformation.Xu, Gang, et al. “Surge of neurophysiological coupling and connectivity of gamma oscillations in the dying human brain.” Proceedings of the National Academy of Sciences, vol. 120, no. 19, 2023. PMC – PubMed, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10175832/.