For any part of "you" to survive death that part would also have to be able to survive any amount of brain injury or mental illness in life.
After all your "soul" would have to first survive life in order to survive death wouldn't it?
People who have survived damage can have personality changes so great that the people who knew them no longer believe them to be the "same" person
Phineas Gage is probably the most famous of these when in 1848 he survived an explosion that sent a rod through his head?
What happened to his soul? His personality was utterly changed where did this new Gage come from?
If the fundamental character of Phineas Gage was unable to survive a brain injury how could it survive death?
http://serendip.brynmawr.edu/bb/neuro/neuro02/ web2/adymkowski.html