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How Long Is There Brain Activity After Death

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What Happens When There Is No Brain Activity

Your brain still works after death

When someone is brain dead, it means that the brain is no longer working in any capacity and never will again. Other organs, such as the heart, kidneys or liver, can still work for a short time if the breathing machine is left in place, but when brain death is declared, it means the person has died.

The Research Could Have Huge Medical And Ethical Implications For Things Such As Organ Donation

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Brain activity may continue for more than 10 minutes after the body appears to have died, according to a new study.

Canadian doctors in an intensive care unit appear to have observed a person’s brain continuing to work even after they were declared clinically dead.

In the case, doctors confirmed their patient was dead through a range of the normal observations, including the absence of a pulse and unreactive pupils. But tests showed that the patients brain appeared to keep working experiencing the same kind of brain waves that are seen during deep sleep.

In Dying Brains Signs Of Heightened Consciousness

We often talk about death as a point in time. One moment youre alive and the next, when your heart stops beating and your lungs stop breathing, you are clinically dead. This definition tempts us to view death as a clear-cut event, like the flip of a switch.

Thats not how Jimo Borjigin, a neuroscientist at the University of Michigan, sees it. Doctors assume that after clinical death, the brain is dead and inactive, she says. They use the term unconscious again and again. But death is a process. Its not a black-or-white line.

In a new study, Borjigin discovered that rats show an unexpected pattern of brain activity immediately after cardiac arrest. With neither breath nor heartbeats, these rodents were clinically dead but for at least 30 seconds, their brains showed several signals of conscious thought, and strong signalsto boot. This suggests that our final journey into permanent unconsciousness may actually involve a brief state of heightened consciousness.

But Borjigins research suggests that these experiences could just be a natural product of a dying brain. That doesnt make them any less real, but it does root them in the natural world, without the need for a super- prefix.

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When Pigs Die Can Their Brains Be Revived

In the study, scientists took brains from pigs that had been slaughtered at USDA-regulated facilities, connected them to a machine that pumped an artificial blood-like nutritional fluid through the brains four hours after their death, and measured activity of brain cells. They found that even hours after death, blood circulation or circulation of the artificial blood and certain brain cell functions could be restored in this experimental setting.

The conclusion was that demise in the brain after the heart stops beating follows an extended process rather than occurring at a defined moment in time, and that perhaps our brains have a better capacity to heal than is currently known.

Is this news? Yes, on a scientific level that is, under the microscope, because an experiment like this has not been done before. But, have we not known for a long time that death does not occur within the blink of an eye?

Historic accounts of decapitated bodies taking a few steps or even running.

That means that such a body was not immediately dead. And, conceivably, if one hooked up such a body to blood supply and healed the wounds, most people could likely imagine that it could continue to be maintained with living body parts or cells.

How Long Will A Brain

Doctors Record Brain Activity After Death

A 13-year-old girl in California continues to be on a ventilator after being declared brain-dead by doctors. Although a brain-dead person is not legally alive, how much of the body will keep on working with the help of technology, and for how long?

Jahi McMath of Oakland, Calif., was declared brain-dead last month after experiencing an extremely rare complication from tonsil surgery. Jahi’s family members have fought to keep their daughter on a ventilator, but a judge has ordered that the machine be turned off next week.

A person is considered brain-dead when he or she no longer has any neurological activity in the brain or brain stem meaning no electrical impulses are being sent between brain cells. Doctors perform a number of tests to determine whether someone is brain-dead, one of which checks whether the individual can initiate his or her own breath, a very primitive reflex carried out by the brain stem, said Dr. Diana Greene-Chandos, an assistant professor of neurological surgery and neurology at Ohio State University Wexner Medical Center. “It’s the last thing to go,” Greene-Chandos said.

In the United States and many other countries, a person is legally dead if he or she permanently loses all brain activity or all breathing and circulatory functions. In Jahi’s case, three doctors have concluded that she is brain-dead.

With just a ventilator, some biological processes including kidney and gastric functions can continue for about a week, Greene-Chandos said.

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Evolution Of The Criteria For Brain Death

Historically death was defined by the presence of putrefaction or decapitation, failure to respond to painful stimuli, or the apparent loss of observable cardio respiratory action. The widespread use of mechanical ventilators that prevent respiratory arrest has transformed the course of terminal neurologic disorders. Vital functions can now be maintained artificially after the brain has ceased to function. In 1968, an ad hoc committee at Harvard Medical School reexamined the definition of brain death and defined irreversible coma, or brain death, as unresponsiveness and lack of receptivity, the absence of movement and breathing, the absence of brain-stem reflexes, and coma whose cause has been identified.

At Hour 12 And Beyond

After reaching a state of maximum rigor mortis, the muscles will begin to loosen due to continued chemical changes within the cells and internal tissue decay. The process, known as known as secondary flaccidity, occurs over a period of one to three days and is influenced by external conditions such as temperature.

During secondary flaccidity, the skin will begin to shrink, creating the illusion that hair and nails are growing. Rigor mortis will then dissipate in the opposite directionfrom the fingers and toes to the faceover a period of up to 48 hours.

Once secondary flaccidity is complete, all of the muscles of the body will again be relaxed.

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Are There Drugs That Can Stop The Brain From Working And Give A False Diagnosis

Certain drugs can mask brain function, such as muscle relaxants and sedatives. Testing can only be done when the individual has low levels of these drugs in the body. It may be necessary to wait for these levels to go down. The doctor can then accurately measure brain activity. Sometimes, other tests are done to confirm brain death if certain drugs are present in the body.

What Happens During Cardiac Arrest

Is A Brain Dead Person Actually Dead?

During cardiac arrest, unconsciousness will occur rapidly once the heart stops beating, typically within 20 seconds. Deprived of the oxygen and sugars it needs to function, the brain will be unable to deliver the electrical signals needed to sustain organ function, including breathing.

This can lead to a hypoxic-anoxic injury . Hypoxia refers to a partial lack of oxygen, while anoxia indicates a total lack of oxygen. In general, the more complete the deprivation, the more severe the harm to the brain.

With cardiac arrest, the lack of circulation affects not just one part of the brain but everywhere in the brain where blood flows. An injury caused by apoxia is referred to as diffuse brain damage. Among the parts of the brain most vulnerable to injury is the temporal lobe where memories are stored.

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Brain Death Is Not The Same As Coma

Brain death differs from other states of unconsciousness in important ways. For example, coma is similar to deep sleep, except that no amount of external stimuli can prompt the brain to become awake and alert. However, the person is alive and recovery is possible. Brain death is often confused with a persistent vegetative state, but these conditions are not the same either. A persistent vegetative state means the person has lost higher brain functions, but their undamaged brain stem still allows essential functions like heart rate and respiration to continue. A person in a vegetative state is alive and may recover to some degree, given time. Brain death means the person has died.

After Death Some Cells In Human Brain Remain Active: Report

Researchers at the University of Illinois at Chicago analyzed gene expression in fresh brain tissue and found that gene expression in some cells actually increased after death.

In the hours after we die, certain cells in the human brain are still active. Some cells even increase their activity and grow to gargantuan proportions, according to new research from the University of Illinois Chicago.

In a newly published study in the journal Scientific Reports, the UIC researchers analyzed gene expression in fresh brain tissue — which was collected during routine brain surgery — at multiple times after removal to simulate the post-mortem interval and death. They found that gene expression in some cells actually increased after death.

These ‘zombie genes’ — those that increased expression after the post-mortem interval — were specific to one type of cell: inflammatory cells called glial cells. The researchers observed that glial cells grow and sprout long arm-like appendages for many hours after death.

“That glial cells enlarge after death isn’t too surprising given that they are inflammatory and their job is to clean things up after brain injuries like oxygen deprivation or stroke,” said Dr. Jeffrey Loeb, the John S. Garvin Professor and head of neurology and rehabilitation at the UIC College of Medicine and corresponding author on the paper.

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Brain Death Is Different From Vegetative State

The difference between brain death and a vegetative state, which can happen after extensive brain damage, is that it’s possible to recover from a vegetative state, but brain death is permanent.

Someone in a vegetative state still has a functioning brain stem, which means:

  • some form of consciousness may exist
  • breathing unaided is usually possible
  • there’s a slim chance of recovery because the brain stem’s core functions may be unaffected

Someone in a vegetative state can show signs of being awake. For example, they may open their eyes but not respond to their surroundings.

In rare cases, a person in a vegetative state may show some sense of response that can be detected using a brain scan, but not be able to interact with their surroundings.

Brain Cells Get More Active After We Die And Even Grow Finds Study

Brain Activity Restored Four Hours After Death In A Recent ...

Researchers have discovered that some brain cells in a human body get more active, hours after the death of an individual, resulting in some cells spreading for hours.

It was already established that our cells can stay alive and even function normally until they gradually go offline. However, every cell, despite the same genetic information, expresses the information in its own way. And when researchers observed the gene expression of cells of the dying brain, they found some rather surprising irregularities.

In the study, researchers looked at samples of brain tissue donated by patients who had recently undergone brain surgery for epilepsy. In case you didnt know, in such surgeries, parts of the brain are surgically removed that are linked to seizures.

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Can A Head Still Be Alive After Decapitation

Even worse to imagine: Could the decapitated head still be conscious for a bit? Perhaps yes.

After the heart stops beating, we consider that someone has died. But, after the heartbeat stops, we also know that sometimes, the heartbeat can come back by itself. This is called autoresuscitation. In this case, someone that appeared dead for a few minutes may not have actually died.

But the situation is different for the brain than for the heart. When there is a lack of blood flow in the absence of a heart that pumps it, or when there is intrinsic brain injury and blood cannot get in, the situation is tricky. Brains are very sensitive to being deprived of oxygen and energy supply, and various degrees of brain injury occur. Depending on how long the energy fuel to the brain is absent, brain function can remain alive to various degrees and be rekindled to a degree we neuroscientists do not yet fully know. We know that brain function is seriously disturbed, with variable permanence of function loss depending on how long the brain has not had energy.

The end result of how functional such a damaged brain will come out is one of the biggest challenges we have to learn more about.

After an injury, a whole sequence of consecutive processes occurs that is called secondary brain injury and is triggered by the insult to the brain in the first place. And these processes often cause tremendous damage, and sometimes more than the actual first injury.

What Happens After Decapitation

It is necessary to understand a bit about how the brain works to get a handle on this whole matter. What we know as brain activity is due to the electrical activity of the neurotransmitter chemicals in our brains that help neurons to communicate with each other and form neural networks. Everything we think about and feel is due to the pathways and activities of our neural networks.

The brain requires a constant supply of blood and oxygen to remain functional and keep the neural networks working. If these supplies are cut off, the brain will die. Decapitation severs the blood and oxygen supplies to the brain, and the inevitable happens. The person dies. The question is, how soon does death occur? Immediately? After a few seconds or after a few minutes? And, if it is after some seconds or minutes, does the brain retain its ability to think and feel in this time? Does the person experience grief and pain?

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What To Learn From The Pig Study

The study of revived pig brain cells does not even come close to touching on this much bigger picture. It is limited to showing that the time span and spectrum of nerve cell function that can persist and at least partially be restored is longer than had been shown so far. Hence, it supports the idea that dying is a process, and puts an additional piece of data on the length of this process.

But it does not show that these brain cells were able to function as a nerve cell network leading to higher brain function such as consciousness or awareness the features that set us apart as humans. It also just looks at the immediate restoring of cell function, and not at how these brains do days out, when the continuing processes of secondary brain damage set in.

To summarize, in the absence of blood flow, the brain, including all its individual cells will die eventually. And this study has perhaps expanded the understanding of eventually.

Death is a process, and not a moment in time. It is the human desire to put things in categories of black and white, and to have definitions that let us operate in daily life. Death this is becoming more and more clear is a large gray zone, and we will have to expect that this gray zone grows as science progresses.

Postmortem Gene Expression And Neurological Disorders

Brain Activity Found in Deceased Patient 10 Minutes After Death

In a news release, researcher Dr. Jeffrey Loeb explained that the postmortem behavior of glial cells isnt particularly surprising. They are inflammatory and their job is to clean things up after brain injuries like oxygen deprivation or stroke, Loeb said. However, the implications of the findings could be profoundly important to the study of neurological disorders. As Science Daily explains, most research that uses postmortem human brain tissues to study neurological disorders does not account for postmortem cell activity. Most studies assume that everything in the brain stops when the heart stops beating, but this is not so, Loeb said. This could revolutionize the study of neurological disorders ranging from autism spectrum disorders to Alzheimers disease. Our findings dont mean that we should throw away human tissue research programs, it just means that researchers need to take into account these genetic and cellular changes, and reduce the postmortem interval as much as possible to reduce the magnitude of these changes, Loeb said.


As expected, the behavior of brain cells like glial cells in the postmortem period has far-reaching consequences. This groundbreaking understanding of gene and cell behavior can inform the study of neurological conditions. From Alzheimers disease to autism spectrum disorders, the study could revolutionize future treatments.

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Pig Brains Kept Alive Outside Body For Hours After Death

The pigs whose brains were used in the study had been killed at a slaughterhouse for meat.Credit: Chaiwat Subprasom/Reuters

In a challenge to the idea that brain death is final, researchers have revived the disembodied brains of pigs four hours after the animals were slaughtered. Although the experiments stopped short of restoring consciousness, they raise questions about the ethics of the approach and, more fundamentally, about the nature of death itself. The current legal and medical definitions of death guide protocols for resuscitating people and for transplanting organs.

Details of the pig-brain experiments appear in a paper published on 17 April in Nature. Researchers at Yale University in New Haven, Connecticut, hooked the organs to a system that pumped in a blood substitute. The technique restored some crucial functions, such as the ability of cells to produce energy and remove waste, and helped to maintain the brains internal structures.

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