Most people often regard death as a point in time, or a matter of a moment. A person is still alive at a moment, and at the next moment, when his heart stops and his lungs are gone, he is called clinical death. This definition makes it easy to think of death as a clear-cut event, like the opening and closing of a switch. But neuroscientist Jimo Potjikin of the University of Michigan does not agree with this definition. She said doctors usually assume that the brain is dead after clinical death. “Disappearance of consciousness” is a word repeatedly used by doctors, but Potikin and others believe that death is a process, not a black and white line.
Is the mouse more aware after death?
In a study published in August 2013, Bojikin found that the experimental mouse had an unexpected pattern of brain activity after the heartbeat had just stopped. Without the heartbeat and breathing, these mice died clinically, but within at least 30 seconds, their brains showed multiple signs of conscious thinking, in addition to some stronger signals. Although the subjects of these experiments are mice, Bojikin thinks that they also have meaning for the “death experience” of human beings.
One out of every five people who survived cardiac resuscitation after cardiac arrest reported a “sudden death experience”. Although they were unconscious during the clinical death and did not respond to the stimulus, after the recovery they described the experience of seeing the light, “realistic than the real situation”, meeting with relatives and friends, and “soul out” (collectively referred to as “the death experience” “). Mainstream scientists believe that these claims are purely nonsense. Others use the “death experience” as evidence that “the soul exists independently of the body” or “afterlife”. But Bojikin’s research suggests that the “death experience” may still be a natural product of the brain that is dying. This view does not deny the true existence of the “death experience” but attribute them to the natural world, not to superstition.
This study by Potjikin et al. began in 2007. At the time, they were studying brain activity after a stroke in experimental rats. In the experiment, 3 rats died unexpectedly overnight. When the researchers discovered that they were dead the next day, they noticed several strong signal spikes in the brain after the death of the mouse (referred to as cardiac arrest, clinical death). Bojikin believes that if the mouse brain is still active after the heartbeat is stopped, then this activity can be measured.
Subsequently, the team led by her team implanted multiple electrodes into the brains of nine experimental mice and measured their brain waves (the rhythmic pulses of neural activity, expressed in Greek letters according to frequency). They first anesthetize the mouse, then stop the heartbeat of the mouse by injecting the drug, or kill the mouse with a lethal dose of carbon dioxide. When the heartbeat of the mouse stops, most of the brain waves also weaken over time. But there is a brain wave — the low gamma wave that occurs when a neuron fires 22 to 25 times per second — becomes stronger in a short period of time, and this is the case for nine mice. It is not surprising that they still have brain waves after the clinical death of the mice, but they are surprised at the high intensity of this brain wave. In addition, the activities of different parts of the mouse brain have become more synchronized. In particular, their low gamma waves are twice as synchronized in the state of sudden death as they are under anesthesia or waking.
In early research, these characteristics have been linked to conscious cognition. For example, when people recognize a face in some random patterns, the low gamma wave suddenly becomes synchronised with the distant brain. This does not seem to be difficult to understand, because the recognition behavior uses the visual center of the brain and the brain area responsible for facial recognition and memory. Neurons throughout the brain need to initiate an overall response and fire together.
Conscious thinking is also linked to the strength of the connection between multiple front parts of the brain (which are associated with many complex mental abilities) and multiple parts of the back (they process sensory information). The Potigkin team noted that the strength of the connections in these areas was 6 to 9 times that during the cardiac arrest of the mice during their anesthesia or during waking. They were amazed at this and thought it would help explain why people with a “death experience” can “see” and “listen” during their clinical death.
Stephen Loris, the leader of the “Coma Science Group” at the University of Liege, Belgium, pointed out that “the experience of sudden death” should be a physiologically true phenomenon, but science and medicine have not taken them seriously for a long time. He pointed out that scientists can not just listen to the patient’s telling story about the “death experience”, but need to measure the brain activity of the patient during sudden death, and the research on the state of sudden death should be strengthened. Lorris also compared the study of the “death experience” with the growing understanding of dreams. For a long time, scientists only explored the dreams from the various dream stories told after people wake up, but the electrode measurement reveals the neurological basis of dreams, including the existence of rapid eye movement sleep, and most dreams occur. In this sleep stage. Lorris believes that this inspires us to conduct such research on the “death experience.”
But Lorris also reminded that the scientific community is still arguing which neural signals are the markers of consciousness, so it is not just a matter of decoding the brain model of the experimental mouse seen by the team. Can these patterns explain what mice actually think during clinical death? Or did the mouse really experience it at the time? Questions like this are hard to answer. Lorris also pointed out that the study by the Potjikin team has undoubtedly shown that EEG activity during clinical deaths is much more and more interesting than previously expected by the scientific community. Although mouse studies are easily linked to the “death experience” of humans, they must be very cautious when doing so.
Some scientists pointed out that the experimental results of the Potikin team can also be explained. When blood no longer flows to the brain, calcium is poured into the brain cells, which eventually leads to cell damage and death. This process can result in measurable EEG activity, which may be the result of the Potikin team. This also explains why the Potikin team saw the same EEG pattern in every dying mouse, but only 20% of clinical death recoverers had a sudden death experience.
The scientists also pointed out that other studies of EEG during clinical death in patients did not find similar patterns, suggesting that the experimental methods of the Potikin team may be problematic. But Pojikin countered that the other teams mostly placed the electrodes on the patient’s scalp, while her team implanted the electrodes directly into the mouse’s brain, making the measurements more sensitive to weak signals. In Podkin’s view, these signals are a sign of increased consciousness. She speculates that this kind of brain activity spike may be a natural defense: when the brain is in a critical state, it needs to be highly vigilant so that people can deal with the crisis. This raises other interesting questions that are not related to the “death experience”. Bojikin did not realize that when the supply of oxygen and glucose stopped, the brain would have a stronger consciousness. So, is this happening when we are awake or when we are sick, praying or meditating? If so, can it stimulate hallucinations or artistic inspiration? There are currently no answers to these questions.
Similarly, the experimental results of the Potigkin team are also seen by some as evidence of the existence of “post-death consciousness” or “soul”. They actually deliberately ignored the conclusion of this experiment – “the experience of sudden death” is the natural product of the dead brain. In other words, if the brain is really dead, there is no consciousness; and if the brain (of course, it is also part of life) is not dead, how can its consciousness activity be counted as “post-death consciousness”? So, where is the “post-death consciousness”?
It is also worth mentioning that as early as 2011, a similar study at the University of Nijmegen in the Netherlands caused some concerns. At that time, in order to determine a common method of euthanasia of the experimental mouse, whether the dagger was humane, the researchers connected the EEG to the mouse brain, then daggered the mouse, and recorded the electrical activity in the brain of the mouse after being decapitated. It was found that after the mouse’s body was separated, the brain continued to produce electrical activity between 13 and 100 Hz, which is related to consciousness and cognition. This finding suggests that after being decapitated, the mouse brain can continue to produce thought and experience for at least a few seconds. Although the discovery in mice can often be extended to humans, scientists may never know whether a person will remain “conscious” after losing his head. The reason is simple – it is impossible to conduct such an experiment.
How long can a person remain conscious after being beheaded? This issue is still controversial. After the chicken is beheaded, the body usually walks for a few seconds. Early studies found that mice were able to remain conscious for about 4 seconds after being decapitated. Other studies of small mammals have shown that this time can be as long as 29 seconds. If the person is beheaded after the decapitation, it will not cause great anxiety.
Why can a broken head live for a few weeks?
The hardships of cockroaches are notorious, they are often said to be the animals most likely to survive the nuclear war. Some people even say that you can live without your head. This statement turned out to be correct – the head of the head lost, actually can live for a few weeks!
To understand why cockroaches (and many other insects) survive after a broken head, you must first understand why people can’t. First, people who are beheaded can cause blood loss and blood pressure to drop, which prevents oxygen and nutrients from being transported to important tissues, so people bleed to death. In addition, when the person breathes through the mouth or nose, the brain controls this important function, so the person’s breathing is stopped after being decapitated. Not only that, the human body can’t eat without a head, which makes the decapitated person starve to death quickly—even if he can survive other bad effects related to losing his head.
But there is no blood pressure like humans, no huge vascular network like humans, and no tiny capillaries that require a lot of pressure to let blood pass. The sturdy circulatory system is open, and the pressure required is much lower. If the head is cut, it is common for their neck to close by coagulation without uncontrolled bleeding.
The tough cockroaches breathe through a small hole in the body section, the breathing hole. In addition, the brain does not control this breathing, and the blood does not deliver oxygen to the body. Through a set of pipes – the breathing tube, the breathing holes of the jaws send the air directly to the whole body tissue. Quails are also cold-blooded insects, which means they require far less nutrients per gram of body weight than humans. Insects only need to eat for a day, enough to survive for several weeks without eating. As long as no predators eat them, they are not easy to die unless they are infected with mold, bacteria or viruses.
Entomologists have carefully decapitated the American cockroach (a kind of cockroach) under a microscope, and then sealed the wound with dental wax to avoid dehydration and death. As a result, two donkeys were decapitated and lived in the jar for several weeks. Each segment of the insect has a pile of ganglia that perform basic neurological functions for physiological reflexes. Therefore, even if the brain is lost, the body of the insect can still make simple reactions, such as standing up, responding to touch and moving.
Not only can the body survive after being decapitated, but the falling head can also wave the antennae for hours before and after the head is dehydrated. If given nutrients and being frozen, the body and head after being decapitated can survive for a longer period of time. However, for cockroaches, the body still provides a lot of sensory information to the head. When these inputs are deprived, the brain can no longer function properly. For example, despite their good memory, after they lose their heads, no matter what scientists teach them, they can no longer be remembered.
Daggers may sound terrible, but scientists have conducted many experiments on headless and bodyless heads. Daggers will prevent the body from getting hormones from the glands of the head, and these hormones control growth, which helps researchers investigate insect deformation and reproduction. Studying the head of the lost body helps to reveal the mechanisms by which their neurons work. In addition, of course, it can provide another conclusive evidence for the embarrassing tenacity.
Why is the snake head cut off?
The National Geographic website reported on August 13, 2013 that a video that was madly transmitted on a video site showed that the head of a wild copper snake had been cut to bite its body. In the video, the cut snake head lay lazily beside its body that had been cut. After the video started for 26 seconds, the average person would think that the snake was dead and upturned, and the snake head flew up and inserted the fangs into his tail. Throughout the video, there has been an exclamation of the first snake (a man from Alabama, USA): “This is crazy! How can you eat yourself? You guy, don’t you know? Eat your own tail? My God!”
In fact, when the snake head flew up, it was one hour since the snake was decapitated, which is what an ordinary person thinks has been dead for an hour. Scientists explained that when the snake’s head was cut, the basic functions of the snake’s head and body stopped, but there were still some reflexive movements. In other words, even if the snake’s body is separated, even if the snake is really dead, the snake head is still capable of making a bite and spraying venom. As for the snake in the video, why do you want to bite yourself? It is very simple – because the snake’s body is just next to the snake head that was cut. Even if the snake head is taken somewhere else, it can continue to bite and continue to open his mouth. This is why snakes sometimes bite themselves, especially when they are excited and don’t care what they are trying to bite.
So, will the snake be poisoned because he bites himself? This issue is still controversial. Snakes that are caught sometimes bite each other, causing the death of another snake of the same species. But the question is, is the snake that was killed by death killed by the mechanical force of being bitten, or was it poisoned?