jan; they're amputees. and for them, the project has found a way to connect the arm without brain surgery. 57-year-old johnny matheny lost his arm to cancer. dr. albert chi, from johns hopkinsospital, found the nerves that used to go to johnny's hand and moved them to healthy muscles in his remaining limb. >> albert chi: now, elbow extension. >> pelley: sensors on his skin pick up the brain's signals from the nerves and use those signals to control the robotic arm. >> johnny matheny: come here, i want to see you. >> pelley: so even though the limb is missing, the brain still sends the signals as if the limb was still there? >> chi: correct. >> pelley: johnny, it feels in... in your mind like your hand is... is there again? >> chi: yes. >> pelley: as if your arm had never been lost? >> matheny: correct. >> pelley: unlike jan, the connection for johnny runs both ways. sensors in the fingers send signals back so he can feel what he's touching. okay, i'm holding the object and you can close on it. to see how well, we put him to the test. hard or soft? >> matheny: soft. >> pelley: correct. very good. now, let's try again. i'm holding the object. hard or soft? >> matheny: soft. >