After several hours the rat realized it no longer needed to press the bar. If it just looked at the bar and imagined its forelimb pressing it, its neurons could still express the firing pattern that our brain-machine interface would interpret as motor commands to move the lever. Over time, four of six rats succeeded in this task. They learned that they had to “think through” the motion of pressing the bar. This is not as mystical at it might sound; right now you can imagine reaching out to grasp an object near you–without doing so. In similar fashion, a person with an injured or severed limb might learn to control a robot arm joined to a shoulder.