In 1977 Barlow and two of his graduate students severed the optic nerve in the crab's lateral eye and continued to measure the eye's sensitivity to light. The eye stopped making rhythmic changes and became a static organ. They then recorded the neural activity from the part of the severed nerve that was still connected to the brain. When they attached an electrode to the end of the nerve still attached to the eye and played the neural activity recorded from the brain, the eye converted to its highly sensitive night time state. The experiment showed that electrical impulses from the brain were responsible for the daily changes in the eye. Barlow and his team have worked out methods for recording impulses from a single optic nerve fiber. And from all of these studies they have learnt much about the human eye and its communications with the human brain.