I read an article some time back about an opera singer who suddenly had to retire. When she sang, her throat would "open" and "close" automatically, but one day the process suddenly was no longer unconsciously controlled by the brain, so she had to do it consciously. But this wrecked her singing.
Or another example: http://www.medhelp.org/posts/Respiratory-Disorders/Suddenly-not-inhaling-automatically-anymore/show/1661016 A person suddenly stopped inhaling automatically, so she could not fall asleep. Every time she did, she would awake gasping for air because her body "forgot" to breathe.
What is the general term for this occurrence?