“Brain cells are very sensitive to a lack of oxygen. Some brain cells start dying less than 5 minutes after their oxygen supply disappears.
A: It's possible to keep an isolated brain alive, but only briefly. And for ethical and practical reasons, many experts steer clear of this scenario. Scientists first kept a mammalian brain alive outside its body for about eight hours in the early 1990s.
In one possible situation, a brain that has been removed from its host is able to sustain consciousness using the oxygen and nutrients necessary for function delivered via some kind of apparatus. This is called the ex cranio brain.
Brain cells can live at least twice as long as the organisms in which they reside, according to new research.
Lorenzo Magrassi, a neurosurgeon at the University of Pavia in Italy. So if the human life span could be stretched to 160 years, "then you are not going to lose your neurons, because your neurons do not have a fixed lifetime."
Decomposition often occurs within minutes after death, which is quicker than other body tissues, likely because the brain is about 80% water. Rotting starts in normal ambient temperature at about 3 days, and the brain is essentially vaporized within 5-10 years.
The difference between brain death and a vegetative state (a disorder of consciousness), which can happen after extensive brain damage, is that it's possible to recover from a vegetative state, but brain death is permanent.
Lorber had subjected his patients to CAT scans and found that while most of them were mentally impaired, some, even when their brain filled no more than 5% of the cranial cavity led normal lives.
Time is very important when an unconscious person is not breathing. Permanent brain damage begins after only 4 minutes without oxygen, and death can occur as soon as 4 to 6 minutes later.
It is likely that humans are born with all of the nerve cells (neurons) that will serve them throughout life. For all practical purposes, when our neurons die, they are lost forever.
If we don't even know how much information storage a human brain can hold, you can imagine how hard it would be to transfer it into a computer. You'd have to first translate the information into a code that the computer can read and use once it is stored. Any error in doing so would probably prove fatal.
Even though the cerebellum has so many neurons and takes up so much space, it is possible to survive without it, and a few people have. There are nine known cases of cerebellar agenesis, a condition where this structure never develops.
In particular, the temporal lobe (at the temples) is sensitive to oxygen deficiency which is also where the memory is situated. A lack of oxygen from three to nine minutes can result in irreversible brain damage!
Cardiopulmonary resuscitation (CPR) is inherently less efficient at delivering blood and oxygen to the brain than a beating heart. Even when CPR is performed according to guidelines, it can only deliver approximately 20 percent of normal blood flow to the brain.
According to the University of California, Santa Barbara's UCSB ScienceLine website, the brain can withstand three to six minutes without oxygen before brain damage occurs.
Cardiac arrest can be fatal if it lasts longer than 8 minutes without CPR. Brain damage can happen after just 5 minutes. Cardiac arrest treatment should start right away, even if you're not in the hospital.
The amount of information the brain can store in its many trillions of synapses is not infinite, but it is large enough that the amount we can learn is not limited by the brain's storage capacity. However, there are other factors that do limit how much we can learn. The first is our limited attention.
Missing All but the Brain Stem
Trevor Waltrip, born in Louisiana on Christmas Eve in 2001, has defied the odds for 12 years. He lived without any brain at all save the brain stem. Trevor was born with a rare condition called hydranencephaly, which replaced his neural tissue with cerebrospinal fluid.
Even if the brain does not age, transplant would not be possible due to many reasons, one of which is immune responses. Immune response is a way our bodies are protected against pathogens like bacteria and viruses.
Sadly, no one has ever recovered after being declared brain dead. What does brain death look like? Brain dead patients look asleep, but they are not. They do not hear or feel anything, including pain.
Once the brain stem has permanently stopped functioning, there's no way of reversing it and the heart will eventually stop beating, even if a ventilator continues to be used.
Even though those in a persistent vegetative state lose their higher brain functions, other key functions such as breathing and circulation remain relatively intact. Spontaneous movements may occur, and the eyes may open in response to external stimuli. Individuals may even occasionally grimace, cry, or laugh.
The body does not feel pain during cremation because the person is no longer alive. When a person dies, their brain stops sending signals to the body. This means that the person cannot feel pain or any other sensation. In fact, a dead person feels nothing at all.
One of the wildest innovations is “living funerals.” You can attend a dry run of your own funeral, complete with casket, mourners, funeral procession, etc. You can witness the lavish proceedings without having an “out-of-body” experience, just an “out-of-disposable-income” experience.
Death just became even more scary: scientists say people are aware they're dead because their consciousness continues to work after the body has stopped showing signs of life. That means that, theoretically, someone may even hear their own death being announced by medics.