Rich Shewmaker said:Your suggestion led me to search urban legend sources where I found this:
http://www.snopes.com/science/stats/10percnt.htm
That's a poorly reasoned article on the subject. For example,
it says:
"But if all those parts of the brain are unused, removal or
damage to the "unused" part of the brain should be minor or
unnoticed. Yet people who have suffered head trauma,
a stroke, or other brain injury are frequently severely
impaired. Have you ever heard a doctor say, ". . . But
luckily when that bullet entered his skull, it only damaged
the 90 percent of his brain he didn't use"? Of course not."
The implication is that severe damage or removal of
part of the brain cannot be minor or unnoticed, but
that is flatly untrue. There have been cases of people
with massive damage to the frontal lobes with minor
or unnoticable changes. That was often the case
with lobotomy patients, in which the entire frontal
lobes were essentially disconnected from the rest
of the brain. Usually, it would result in behavioral
changes, which was the intended result, but if the
operation was performed too conservatively (too
far anterior), there would often be no perceptible
change in the status of the patient.