The most important reason anyone is an atheist

[Sword of Christ]

Two photographic portraits of Gage, and a physician's report of his physical and mental condition late in life, were announced in 2009 and 2010. This new evidence indicates that Gage's most serious mental changes may have been temporary, so that in later life he was far more functional, and socially far better adjusted, than was previously assumed. A social recovery hypothesis suggests that Gage's employment as a stagecoach driver in Chile provided daily structure allowing him to relearn lost social and personal skills.

http://en.wikipedia.org/wiki/Phineas_Gage

Now this in too light with the opposing, we have no examples of a mind without a brain
here is another example in MRI images
Live thinking person

And someone dead from traumatic brain injury

We know for certain that that mind/consciousness is no longer associated with that specific brain but this isn't an earth-shattering revelation.