It’s long been suspected that what we describe as near death experiences (NDEs) may be related to processes in the brain that create a flurry of activity to produce the strange sensations. Those that survive the beginning of the shutdown process may tell about it as a religious or spiritual experience. Well, it’s certainly strange. New research supports the idea that it may be physiological, not supernatural.
The many experiences described by survivors of cardiac arrest — people revived even after their hearts stopped beating, sometimes for many minutes — include moving through a tunnel toward a white light, greeting relatives no longer alive, and overhearing conversations between family members in another room. A new study from the University of Michigan Medical School shows how the brain sends signals to the heart in the moments before death. It is this flurry of mental activity that is key to cardiac demise, the researchers say, and quite probably the foundation of near-death experiences as well.
Including prior research, Dr. Jimo Borjigin explains that the reduction of oxygen during cardiac arrest can stimulate brain activity that may be interpreted as what we call an NDE.
The paper is in the Proceedings of the National Academy of Sciences this week: Asphyxia-activated corticocardiac signaling accelerates onset of cardiac arrest.
The mechanism by which the healthy heart and brain die rapidly in the absence of oxygen is not well understood. We performed continuous electrocardiography and electroencephalography in rats undergoing experimental asphyxia and analyzed cortical release of core neurotransmitters, changes in brain and heart electrical activity, and brain-heart connectivity. Asphyxia stimulates a robust and sustained increase of functional and effective cortical connectivity, an immediate increase in cortical release of a large set of neurotransmitters, and a delayed activation of corticocardiac functional and effective connectivity that persists until the onset of ventricular fibrillation. Blocking the brain’s autonomic outflow significantly delayed terminal ventricular fibrillation and lengthened the duration of detectable cortical activities despite the continued absence of oxygen. These results demonstrate that asphyxia activates a brainstorm, which accelerates premature death of the heart and the brain.
The study was done in mice where they measured brain activity that turned out to be very active during the early stages of death. Scientists suspect that the same thing might happen in humans. The activity can create perceptions of a heightened state of consciousness. But, such a study on humans would be near impossible to do. It may be possible however to use this knowledge of the heart-brain connection in reverse and develop drugs that prevent full cardiac arrest.