That project isn't really as cruel as it seems at first glance. The cells controlling the robot has been cultured outside the rat so they didn't actually extract the entire ratbrain and put it into the robot. Doing a biopsy on the rat for braincells is cruel though.
I don't know how many neurons thats needed before one can say that they form an individual but that robot would be far from it.
On the other hand i get the chill of experiements like this:
RC rats.
Still not close to what humans are capable to in their curiosity...