People who have been close to death often claim to have seen and experienced events like a bright white light at the end of a long tunnel or meetings with lost family members or beloved pets. Despite the apparent supernatural nature of these experiences, science can explain why they take place and what they really are, say British scientists Neil Dagnall and Ken Drinkwater in an article published in The Conversation.
The near-death experiences are "a deep psychological event with mystical elements", experts explain, recalling that this condition may be caused by situations of intense physical or emotional pain, but also after suffering from heart attacks or traumas or even while meditation is practiced
A third of people who have experienced this type of situation say they have experienced common feelings such as feelings of satisfaction, psychic detachment of the body, rapid movements through a long dark tunnel to access a bright light, scientists say.
They also stress that culture and age also play an important role. Thus, for example, many Indians claim to have met Iama, the Hindu god of death, while the Americans say they have met Jesus. Furthermore, children often describe meeting friends and teachers.
In 2009, neuroscientists Olaf Blanke and Sebastian Dieguez proposed two types of near-death experiences. The first type is associated with those cases in which the right hemisphere of the brain is hit, resulting in altered feeling of time and the impression of flying. The second, connected to the damage in the left hemisphere, is characterized by seeing or communicating with the spirits and hearing voices, sounds or music.
Another important role is played by temporal lobes: this area of the brain is involved in the processing of sensory information and memory, so that the abnormal activity in these lobes can produce strange sensations and perceptions.
What is the reason?
Although there are several theories that try to explain the near-death experiences, getting to the bottom of what originates is difficult, say Dagnall and Drinkwater. These point out that religious people believe that these episodes show that life exists beyond death (in particular, the separation of the spirit from the body), while the scientific explanations for this type of phenomena indicate depersonalization, which is how it is defined to the sensation of being separated from the body.
The scientific author Carl Sagan suggested in 1979 that the stress of death produces a memory of birth, suggesting that the "tunnel" that people see is a new image of the birth canal.
Meanwhile, other researchers have attributed these experiences to brain anoxia, the lack of oxygen in the brain. In this sense, there are testimonies of aircraft pilots who have lost knowledge during rapid accelerations and have described similar characteristics to near-death experiences, such as tunnel vision. Lack of oxygen can also trigger convulsions of the temporal lobe, causing hallucinations.
However, the most widespread explanation is "the moribund brain hypothesis", a theory that proposes that near-death experiences are hallucinations caused by brain activity while cells begin to die. However, this theory does not explain the full range of sensations that can be experienced during these episodes, such as out-of-body experiences.