Missing Half Of The Cerebral Cortex
There are a surprising number of known cases of people missing half of their cerebral cortexthe outermost chunk of brain tissue. A currently living and healthy 16-year-old German girl is one. She was born without the right hemisphere of her cortex, though this wasn’t discovered until she was 3 years old. According to her doctors, who published a full case study on her 6 years ago, “despite lacking one hemisphere, the girl has normal psychological function and is perfectly capable of living a normal and fulfilling life. She is witty, charming, and intelligent.”
The physical ailments caused by her missing brain tissue were seizures and a slight weakness on the left side of her body. But here’s something amazing about the way her brain has coped: While most people missing half their cerebral cortex lose sight in one eye, her left eye processes visual information from both the right and left visual field. In other words, her doctors say that while she has no depth perception , her vision is otherwise like that of someone with two eyes, encompassing the entire mental field of vision.
The Challenges Of Defining And Diagnosing Brain Death
A new Johns Hopkins support team helps clinicians and families understand a difficult diagnosis.
A woman lies in a bed at The Johns Hopkins Hospital. Aided by a ventilator, her lungs inflate, deflate, and fill again. Her heart beats and her skin is warm. But her eyes stay closed and she does not react to stimuli such as pain and light.;
Is she alive or dead?
If youre unsure, or if the question makes you uncomfortable, youre not alone. The hypothetical case described here reflects a real problem: the inherent difficulties of diagnosing and accepting brain death.
The topic was the focus of a September Ethics for Lunch discussion in the Chevy Chase Bank Auditorium of The Johns Hopkins Hospital, hosted by the Berman Institute of Bioethics.
The panel was moderated by anesthesiologist and critical care specialist Robert Stevens, who says the line between life and death, once clearly perceptible in the form of a beating heart, is now sometimes harder to see because of advances in lifesaving technologies.
The modern intensive care unit can keep a person with severe brain injuries alive, he says, but may also mask evidence that the person has died. The shift from a deep coma to brain deathpermanent cessation of all brain functionmay not be immediately obvious to an untrained observer. Yet recognizing this transition from life to death is critical for families, the medical team and potential organ recipients.
Watch the Ethics for Lunch panel discussion.;
What Happens When You Damage Your Brain Stem
When an accident causes brain stem damage, the affects can be devastating. In fact, destruction of the midbrain, pons, or medulla oblongata causes brain death, and the unfortunate victim of the injury cannot survive. And while damage to brain stem can cause death, even an injury that does not cause death, can cause significant brain stem injury symptoms. Because so many functions that are essential to survival are located in and pass through the brain stem, an injury to a persons brain stem is often the most devasting injury a person can suffer short of death.
For example, one injury a person can suffer after damage to their brain stem is locked-in syndrome, which is a condition in which a person is fully conscious, but the person cannot move or communicate, except through eye movements or blinking. Despite the devasting effects of the condition, a person suffering from locked-in syndrome can survive for decades in the vegetative state that the syndrome causes.
Brain stem injuries are often severe, even resulting in death, but a lower brain stem injury, while potentially not as serious, can also cause a variety of problems. For instance, a lower brain stem injury can cause loss of consciousness for a few seconds to a few minutes. The injury can cause a person to be dazed, confused, and disoriented. The injury can also cause severe headaches, nausea or vomiting, fatigue or drowsiness, problems with speech, difficulty sleeping, or sleeping more than usual.
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Ruling Out Other Conditions
Before testing for brain stem death can begin, doctors must carry out a series of checks to ensure that the symptoms aren’t being caused by other factors, such as:
- an overdose of illegal drugs, tranquillisers, poisons or other chemical agents
- an abnormally low body temperature
- severe under-activity of the thyroid gland
Once these factors have been ruled out, tests are carried out to confirm brain death. The diagnosis of brain death has to be made by two senior doctors. Neither of them can be involved with the hospital’s transplant team.
The doctors will explain the tests to you and they’ll keep you informed about your loved one’s condition at all times.
Life After Brain Death: Is The Body Still ‘alive’
ByRachael Rettner03 January 2014
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.
Greene-Chandos said Jahi’s case is tragic, and as a mother, she is heartbroken for the family.
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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. His brain stem allowed him to breathe and maintain a heartbeat but little more. He was kept on a feeding tube up until last month, when he passed away peacefully.
Meet The Healthy Functioning Man Who Survived With Almost No Brain
Magnetic resonance image of a normal brain. SMK4pix/Shutterstock.
When it comes to our brains, does size really matter? One of the biggest myths about the brain is that bigger is always better. But what about those who sit on the extreme end of that scale? How much of our brain do we actually need to survive? Looking through the archives of medical history, there are a number of people with tiny brains, or brains with huge chunks missing entirely, which defy all odds. ;
In a 2007 Lancet study, doctors described an incredible medical oddity the 44-year-old civil servant who had lived a normal life despite having an incredibly tiny brain. The French man went into hospital after he experienced weakness in his left leg for two weeks. Doctors were quite surprised when they took scans of his brain and found a huge fluid-filled chamber.
The scans showed that the man had a massive enlargement of the lateral, third, and fourth ventricles, a very thin cortical mantle and a posterior fossa cyst, researchers noted in the study. In short, while fluid normally circulates throughout the brain, its regularly drained. But instead of draining the fluid into the circulatory system, the fluid in this mans brain built up. Eventually, the accumulation of fluid resulted in only a tiny amount of actual brain material. ;
The large black space is the fluid that built up in his brain.;Feuillet et al./The Lancet.
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What Does The Cerebellum Do And Can You Live Without It
The cerebellum is the symmetrical, cauliflower-shaped part of the brain located at the back of your head.
Although it constitutes only one-tenth of the total brain weight, the cerebellum is just as important as all other parts of the brain. Containing billions of densely packed, fully functional neurons, this region of the brain plays a crucial role in many vital processes.
So,;what does the cerebellum do exactly?
In this article, we will answer the most common questions about the cerebellum and its main functions.
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.
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About Brain Stem Death
Brain stem death is when a person no longer has any brain stem functions, and has permanently lost the potential for consciousness and the capacity to breathe.
When this happens, a;ventilator keeps the person’s heart beating and oxygen circulating through their bloodstream.
A person is confirmed as being dead when their brain stem function is permanently lost.
Why Does The Brain Need Oxygen
The brain represents just 2% of a person’s body weight, yet it uses about 20% of the body’s oxygen supply. Without it, the brain can’t perform even the most basic functions. The brain relies on glucose to power the neurons that control everything from conscious functions like planning and thought to automatic, unconscious processes like managing heart rate and digestion.
Without oxygen, the brain’s cells cannot metabolize glucose, and therefore cannot convert glucose into energy.
When your brain is deprived of oxygen, then, the ultimate cause of brain death is inadequate energy to power the brain’s cells.
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How Brain Stem Injuries Happen
Brain stem injuries can occur in a variety of ways from a brain stem injury car accident, to slipping and falling. A brain stem injury resulting from a car accident can even occur through whiplash. Slipping and falling can result in blunt force trauma to a persons head, which can lead to the hemorrhaging mentioned above. One of the most common causes of brain stem injury are Las Vegas motorcycle accidents.
If you have been involved in an accident and have suffered an injury to your brain stem, it is vital that you consult with an attorney. Brain stem injuries are often the most devasting injuries a person can suffer because the care the person will need after the accident is expensive and may be needed for the rest of the victims life.
Furthermore, the injury may take away a persons ability to work. Please contact Las Vegas personal injury attorney firm Valiente Mott for a free consultation today if you have been involved in an accident involving an injury to your brain stem.
How Long Can You Go Without Water
As with food, it is hard to say exactly how long people can survive without water. While a fit adult might last a few days, a child whom a parent or caregiver has left in a hot car could dehydrate and die within hours.
The precise length of time for which a person could survive varies due to differences in individual body composition.
The body needs a continual supply of water to repair and maintain cells and carry out essential processes.
According to the , the symptoms of moderate dehydration are:
- a dry mouth and tongue
- restlessness and irritability
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Missing Half The Entire Brain
In a more severe case, Michelle Mack, a 42-year-old Virginia native, is missing not only half of her cortex but most of the deeper, underlying brain structures on her left side as well. This neural abnormality is believed to be the cause of a prebirth seizure, but was not diagnosed until Mack was 27.
Mack graduated high school and speaks and communicates with some level of normalitythanks to neuroplasticity. But her brain has not faultlessly rewired itself: Mack still has issues comprehending abstract concepts, is prone to emotional distress, and her lowered visualspatial processing ability means that she also is easily lost in unfamiliar surroundings. Yet, living with her parents, she nevertheless manages a productive and fulfilling life.
Can The Mind Exist Without The Brain
In discussions about the mind and its potential to exist apart from or even after the death of the brain, it is common to call upon near death experiences or out of body experiences as evidence for such. It is my belief that sensory experience is a function of the brain, and that a disembodied mind cannot experience these things. Nonetheless, some see the sensory information the mind has been reported to bring back to the body after so-called “near death” experiences as evidence that the mind unfettered by the body retains its full capacity to experience the world.
Let’s extend our thought experiment further to the lesser but no less real modes of sensation. Can the mind that has cast off its mortal coil still experience hunger? Can it experience nausea and vertigo? Can the mind be tickled? Can the mind itch? Is it possible for the disembodied mind to have a toothache? How could the mind have a toothache without a tooth? I suspect it might by the same method it sees without eyes.
There once was a man who said though it seems that I know that I know. But what I’d like to see is the I that knows me when I know that I know that I know.
It is an endless and futile regression. Moreover, I do not see how the notion of a shared, Universal mind, makes this problem any easier than it would be with individual, free floating minds.
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If You Get Your Head Cut Off You Most Likely Will Not Survive How Long Can You Last Until Your Body Finally Shuts Down
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As crazy as it may sound, reports about humans surviving decapitation–heads reacting and even trying to speak–go back several centuries. One particularly chilling story comes from Dr. Gabriel Beaurieux who studied a beheading in 1905. The condemned man’s head was cleanly severed by a guillotine blade and left to fall into a basket at which point the face started twitching. Then, when Beaurieux called out the dead man’s name, the severed head’s eyes lifted up and met Beaurieux’s in the same way that “a person’s would when pulled from a daydream.” There’s some modern scientific evidence to support the idea that the dead man’s look might have been a somewhat conscious reaction.
In 2011, Dutch scientists hooked an electroencephalograph or EEG to the brains of mice, before cutting off their heads. When they measured their post-decapitation brain activity, incredibly, the results showed activity at frequencies of conscious levels for almost four seconds. Similar studies done on smaller animals suggest that brain activity can last even longer once the head is no longer attached to its body.
Coordination Of Muscle Movement
Every movement that you want to make starts as an idea in your brain. As soon as the idea is shaped, a corresponding signal is created in the motor cortex of the cerebrum. This signal then travels to the cerebellum.
The cerebellum is the part of the brain that will relay this signal to instruct all other parts of the body to carry out your planned movement. However, the role of this brain region stretches far beyond that. Rather than just triggering muscle movement, the cerebellum also helps coordinate it.
Lets say that youre a drummer in a rock band. When youre playing, youre not just using your arms. Youre also using your legs. Whats more, your back also plays a part by allowing you to maintain good posture.
All this involves several muscle groups in different parts of your body.
Its your cerebellums task to keep them all in perfect sync while youre performing. If just one group of muscles fails, you wont be able to move your body the way you want to and thus wont be able to create your desired sound.
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How Does Lack Of Oxygen Affect The Brain
Your brain runs your nervous system. It needs oxygen to function. In fact, the brain uses about a fifth of your bodys total oxygen supply. Oxygen helps send nerve signals and messages throughout the body.
When the brain doesnt get enough oxygen, brain cells begin to die. Cell death happens within 5 minutes of low oxygen.