While I understand that neurologic research is important and good, I still find the concept of headless remote controlled flies downright creepy:

Yale University researchers say their study that used lasers to create remote-controlled fruit flies could lead to a better understanding of overeating and violence in humans.

Using the lasers to stimulate specific brain cells, researchers say they were able to make the flies jump, walk, flap their wings and fly.

Via Daffodil Lane, with whom I will have to disagree about the success of "scaling up" this technique to other creatures. The biological complexity of a rat as compared to a fly is astronomical, and I do not expect to see headless remote controlled mice any time soon. Which is just as well. Skeevy!