My understanding is that brain is composed of way more neurons than required, for resiliency. So if it gets a "bruise" in some part, when even a large portion of the cells are dead -- it can still function at 100%. Like a programmer without a finger. The problem is visible only when all the cells in some part are dead.
That's why crows, with their low brain mass are pretty clever (and why all arguments equating brain size and smartness are wrong).
That's why crows, with their low brain mass are pretty clever (and why all arguments equating brain size and smartness are wrong).
Just my layman understanding.