> If they can inject a rat brain with human brain cells and it assimilates, especially in an already developed rat brain, imagine what it could do for people. Inject brain matter to make yourself smarter? Maybe, but probably not? Inject brain matter into the brains of those with a traumatic brain injury or who are otherwise "brain dead"? Might bring people back from the dead. Who knows until we try it?

You probably cant add a noticeable amount of brain mass/cells to a healthy human brain. There really isnt more room.

Any new cells would need to be trained. If you take someone from brain dead to brain alive by adding new brain cells, then you have a new person.