If my brain got damaged i'd happily try to fix it.
Worst case scenario: i die from it
Best case scenario: fully repaired brain
In the middle: it somehow changes who i am

But, will i know it changed me? how will i notice it changed me? And how big can the changes be? Loss of memories? new taste? a new skill? loss of a skill? I personally would happily take it for myself, even if it only helps scientist understand it better. But i doubt i could make that choice for a family member. Maybe..