The brain stem (base of the brain and top of the spinal cord) is marked as the most critical part of your brain. It includes the midbrain, pons and medulla. This brain part controls certain involuntary actions of the body, including your heartbeat and breathing!

If someone has an injured brain stem that won't function, they'd be sent to their grave. Even if your other brain parts are injured or even dead and the brain stem survives, you'd still be alive in a vegetative state. The same doesn't hold true for the brain stem. Without the brain stem, you can't survive—not even in a vegetative state!

A vegetative state is when the cerebrum no longer functions but the brain stem and the hypothalamus are still working! In a vegetative state, you cannot talk or be aware of your consciousness. But a vegetative state is rare, and it can last for as long up to one month.

More Info: www.igeaneuro.com