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.
The brain lives on for 30 seconds after death.
An isolated brain is a brain kept alive in vitro, either by perfusion or by a blood substitute, often an oxygenated solution of various salts, or by submerging the brain in oxygenated artificial cerebrospinal fluid (CSF). It is the biological counterpart of brain in a vat.
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.
About six minutes after the heart stops, the brain essentially dies.
Visions and Hallucinations
Visual or auditory hallucinations are often part of the dying experience. The appearance of family members or loved ones who have died is common. These visions are considered normal. The dying may turn their focus to “another world” and talk to people or see things that others do not see.
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.
Brain death results from swelling in the brain; blood flow in the brain ceases and without blood to oxygenate the cells, the tissue dies. It is irreversible. Once brain tissue dies, there is nothing that can be done to heal it.
Elaine died later that year at the age of 43 years and 357 days, having been in a coma for 37 years and 111 days. Esposito's story was brought back into attention in the late 1990s and early 2000s in the controversy surrounding the case of Terri Schiavo, who was in a persistent vegetative state.
The metabolic needs of vertebrate brains are actually fairly simple – mainly oxygen and glucose. These can be supplied by connecting the blood vessels that supply the brain with an artificial blood substitute or by immersing the blood in an artificial cerebro-spinal fluid and oxygenating that directly.
But it has never been done in humans, mostly because head transplantation would mean cutting the spinal cord, which would cause complete and permanent paralysis. The most reasonable perspective on the soul is that it is the active principle of the body — that is, the soul is what the body does.
These are natural changes that occur while aging. They cannot be stopped but it is possible to slow the rate of these processes. This can be done by changing one's lifestyle (diet, exercise, etc). The science of aging is not yet fully understood; therefore, it is difficult to determine an absolute limit of 200 years.
That's 200 million million—a number too big to visualise. The point is: the brain is a powerful machine. But, like every machine, it has its limitations. If understanding a concept was a recipe, you would need several ingredients: information, memory, and practice, which are all interlinked.
Some people do actually live with half a brain, as a result of a hemispherectomy - surgical removal of half the brain done to control severe cases of seizures. Some other extreme cases include hydranencephaly, where the entire cerebral portion is missing and all that's present is the brainstem.
Variability in the diagnosis of brain death has the potential to lead to misdiagnosis. Even in the clearest circumstances, families may have difficulty accepting a diagnosis of brain death when they see their loved one's heart still beating and feel their body warm to the touch.
In brain dead cases, the spirit or soul is usually out of the body, though often the brain dead person's spirit stays with the body until life support is switched off.
Ethics aside, the brain is a delicate organ, and the spinal cord, which connects to the brain, does not recover well after being cut. While there have been animal experiments involving transplanted heads, most animals that have been subjected to these experiments died within hours or days.
Without oxygen, brain cells die, and a brain injury can occur. It can happen even when enough blood reaches the brain, such as when you breathe in smoke or carbon monoxide. Treatments can help people who have brain injuries from cerebral hypoxia. But no one can bring back dead brain cells or reverse a brain injury.
Comatose patients do not seem to hear or respond. Speaking may not affect their clinical outcome; time spent with them takes time away from other, more "viable" patients. Comatose patients may, however, hear; many have normal brain-stem auditory evoked responses and normal physiologic responses to auditory stimuli.
Life support refers to a variety of medical procedures that aim to keep you alive until your body is ready to take over again. Life support replaces or supports a body function that's failing. Your healthcare providers may use life support until your body can resume normal functioning. Life support doesn't mean death.
It may be a crackling, wet noise that is amplified as the person breathes. In other cases, it may sound like a soft moaning with each breath, or a very loud gurgling or snoring. While the sound may be unpleasant, the person emitting the death rattle usually feels no pain or discomfort.
Agonal breathing or agonal gasps are the last reflexes of the dying brain. They are generally viewed as a sign of death, and can happen after the heart has stopped beating.
The "death rattle" is a gurgling sound you may hear when people die. Because they can no longer swallow or cough, saliva builds up in the back of the throat and upper airways. The fluid causes a rattling sound when air passes through.