New research into the dying brain suggests the line between life and death may be less distinct than previously thought
Patient One was 24 years old and pregnant with her third child when she was taken off life support. It was 2014. A couple of years earlier, she had been diagnosed with a disorder that caused an irregular heartbeat, and during her two previous pregnancies she had suffered seizures and faintings. Four weeks into her third pregnancy, she collapsed on the floor of her home. Her mother, who was with her, called 911. By the time an ambulance arrived, Patient One had been unconscious for more than 10 minutes. Paramedics found that her heart had stopped.
After being driven to a hospital where she couldn’t be treated, Patient One was taken to the emergency department at the University of Michigan. There, medical staff had to shock her chest three times with a defibrillator before they could restart her heart. She was placed on an external ventilator and pacemaker, and transferred to the neurointensive care unit, where doctors monitored her brain activity. She was unresponsive to external stimuli, and had a massive swelling in her brain. After she lay in a deep coma for three days, her family decided it was best to take her off life support. It was at that point – after her oxygen was turned off and nurses pulled the breathing tube from her throat – that Patient One became one of the most intriguing scientific subjects in recent history.
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In the moments after Patient One was taken off oxygen, there was a surge of activity in her dying brain. Areas that had been nearly silent while she was on life support suddenly thrummed with high-frequency electrical signals called gamma waves. In particular, the parts of the brain that scientists consider a “hot zone” for consciousness became dramatically alive. In one section, the signals remained detectable for more than six minutes. In another, they were 11 to 12 times higher than they had been before Patient One’s ventilator was removed.
“As she died, Patient One’s brain was functioning in a kind of hyperdrive,” Borjigin told me. For about two minutes after her oxygen was cut off, there was an intense synchronisation of her brain waves, a state associated with many cognitive functions, including heightened attention and memory. The synchronisation dampened for about 18 seconds, then intensified again for more than four minutes. It faded for a minute, then came back for a third time.
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Something that might be related is the burst of functionality that mammals seem to get, just before dying. In pack animals, an otherwise crippled animal can get up and leave the den. Biologically, this is to get the dead body away from the den site.
Something similar can happen in humans. A dying patient will suddenly perk up and seem to make a miraculous recovery. Nurses unfortunately know that this is false. The patent will burn out and crash soon after. Patents in this state apparently get a feeling of impending doom. This is likely what drives other mammals from the den/nest site.
What they are seeing might be related to this. The brain gives up on survival, in order to try and not risk the health of family members. Often the damage would be too severe, and so the patient doesn't wake up. They just get a burst of neural activity as priorities suddenly change.
This seems very plausible and evolutionarily justified
No it's not to get the dead body away from the site. It's the body, human or animal, giving its last hurrah as a final effort against death. Life, once established is tenacious and doesn't die without a fight if it can help it.
Life attempts to propagate its genes. Just look at salmon, or bees. Both are willing to die to help the next generation.
Leaving a corpse in a den could kill your offspring via disease. Recognising that survival is no longer viable, and acting to protect them makes complete sense.
How do you genetically/evolutionarily select a trait like that? Animals that wander off to die wouldn't be more successful at breeding or survival.
Don't measure by just breeding, measure by how many grandchildren they have.
An animal that has 10 babies, but they all die, doesn't pass on its genes. A wolf that dies in its den, causing some of its offspring to die is hurting its own genetic heritage.
It's also worth noting that genes can be selected for at the tribe/pack level. You don't need to breed, so long as your sisters/brothers/cousins/parents breed.well enough to compensate.
At the extreme, you have things like bees. A normal bee is sterile. It's completely reliant on its specialist brothers and sisters to propagate its genes.
Not directly, but they are more successful in preserving their relatives.
A corpse in the den could attract predators or scavengers and could bring diseases. If the dying animal wander off, the corpse will be found far away from the den so its offspring has a chance to not be found from predators and scavengers and that a disease don't kill/cripple them.