It often kills the person, because the medulla pretty much controls several autonomic functions, like breathing, heart rate, etc.
As a Doctor of Chiropractic, I am the first person in the world (to the best of my knowledge) to "connect the dots" beween the ability of regular upper cervical spinal adjustments (which help improve the function of one's medulla) and improving one's potential potential for success in ALL areas of their life. The medulla contains the Reticular Activating System which is directly involved with our ability to concentrate (to avoid distractions) as well as our ability to set and achieve goals (big or small), to visualize" any successful outcome, etc.
So yes, damage to one's medulla (Brain STEM) can affect one;s mental processes - both our subconscious, automatic goa-striving mechanism as well as our conscious thought. The medulla is our brains "brain" and is responsible for our level of "awakeness"and alertness.
For more information see: www.ML-EI.com
Dr. Kirk McAnsh, D.C.