Developed by researchers at the University of California and California Institute of Technology, the device has enabled people to move a cursor around a screen and also fade and brighten images using just their brain.

The instructions, the researchers said, are enough to play a simple computer game and could eventually allow locked-in syndrome and other brain damaged patients to communicate with the outside world.

Our research showed that "individuals can rapidly, consciously, and voluntarily control neurons deep inside their head", lead researcher professor Christof Koch of California Institute of Technology was quoted as saying by the Telegraph.

For their work, the researchers recruited 12 epilepsy patients who because of their illness had sensors embedded into their brain to monitor nerve activity.They then set about training the volunteers to "exert conscious control" on individual nerve endings or neurons within the brain so that they could be switched on and off using just their thoughts.|

By picking up these "thoughts" using the sensors they could be converted into commands for a computer screen.The scientists looked at the medial temporal lobe -- a region on the left hand side of the brain that plays a major role in human memory and emotion.

Prior to recording the activity, the volunteers were interviewed to find their interests and 100 images created around them.

These were then tested to find the four that showed the strongest correlation response in the brain. These could then be used to control the movement of a cursor or to fade in and out different images.

They also made the participants think of one image, while looking at another to see how the thoughts in the brain competed.It was found that people were able to exhibit conscious control over their unconscious thoughts.

"The patients clearly found this task to be incredibly fun as they started to feel that they control things in the environment purely with their thought, said Moran Cerf, who was also part of the research.

"They were highly enthusiastic to try new things and see the boundaries of 'thoughts' that still allow them to activate things in the environment."