By Simon Hooper for CNN
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LONDON, England (CNN) -- The mysteries of the human mind have tantalized and frustrated philosophers, poets and -- more recently - psychologists for centuries, yet new breakthroughs in neuroscience could mean the brain is finally starting to give up its secrets.
And while "brain caps" enabling us to control computers directly with our thoughts and mind-reading machines may sound like science fiction staples, both are examples of the kinds of technology already being used by researchers to explore, unlock and harness our innermost thoughts.
An exhibition currently on show at London's Science Museum, "NEURObotics... The Future of Thinking?", highlights some of the recent breakthroughs that could mean we will soon be able to give paralyzed patients the ability to control their own movements, restore sight to the blind or simply allow us to augment our senses beyond their natural abilities.
"This technology is here and has the potential to radically affect what it means to be human in the 21st century," said the Science Museum's Emma Hedderwick.
One example that has already demonstrated its therapeutic potential is the "BrainGate" chip implant developed by American scientist John Donoghue, which enabled a fully paralyzed man to control the movement of a computer cursor and a mechanical hand, as reported on Future Summit last year. (Full Story)
Other scientists have developed alternative ways of translating brain activity directly into intelligible information, such as Berlin-based neuroscientist Klaus-Robert Muller whose "brain cap" interface allows users to type words onto a computer screen via a "mental typewriter" after just 20 minutes of practice.
"Complex human-machine interactions are a long way off, but they are possible -- I'm optimistic," says Mueller.
Last month scientists in the U.S. also announced they had partially restored the sight of six blind patients using a robotic retina connected to the brain. Mark Humayun of the University of Southern California, who led the research, says a more sophisticated version could be commercially available within two years.
While the current device enables users to "see" just 16 pixels -- enough to identify simple objects and detect movement -- Humayun says the ultimate goal is to produce a machine with enough resolution to enable users to recognize faces.
"The models suggest 1,000 will be enough for face recognition, and we hope to get there in five to seven years," he told the Times newspaper.
One of the keys to advances in decoding brain activity has been the development of more advanced brain scanning techniques, such as functional Magnetic Resonance Imaging (fMRI) which enables researchers to identify areas of neural activity by monitoring blood flow to the brain.
By mapping which areas are activated by specific activities, researchers are able to identify different thought patterns.
In a recent study by scientists in Germany and the UK led by John-Dylan Haynes of the Max Planck Institute, subjects were asked to add or subtract numbers flashed on a screen. By scanning their brains as they decided, researchers were correctly able to predict their intention. (Full story)
"The consequences of this sort of technology are that we can tell what you're thinking, sometimes even before you know yourself," says Professor Geraint Rees, a neuroscientist at University College London.
"By developing these techniques to decode consciousness, we can understand more about what it is in the brain that actually is consciousness. And if you imagine that I could explain that, I'd be in a position then -- in principle -- to directly decode your thoughts."
The ability to tell what somebody is thinking could have important medical implications for patients unable to communicate their thoughts explicitly, Rees says, highlighting work carried out by Cambridge neuroscientist Adrian Owen in which a woman in a permanent vegetative state was shown to be able to understand and respond to instructions from researchers through brain scans.
But other scientists and sociologists believe that a deepening understanding of brain function could have unintended consequences and serious social and ethical implications for "mental privacy."
In the U.S., "brain fingerprinting" -- a sophisticated form of lie detector test based on brain imaging -- has already been admitted as a form of evidence in some court cases. "The potential for surveillance of citizen's thoughts has moved far beyond the visions of 1984," wrote the British biologist Steven Rose in a Guardian article last year calling for a public debate on the future uses of neurotechnology.
"These technologies, for the first time, give us a real possibility of going straight to the source to see what somebody is thinking or feeling, without them having any ability to stop us," Hank Greely, director of Stanford University's Center for Law and the Biosciences, told The Associated Press.
"The concept of keeping your thoughts private could be profoundly altered in the future."
In the short term however, the practical consequences are more likely to mean better therapies for the severely disabled, says Rees.
"If you look at where the technology is now it is pretty rudimentary," he says. "I don't think in 10 or 20 years there's going to be a helmet you put on that will make a robot exoskeleton walk around if you're paralyzed. But devices like the brain typewriter already work at a functional level and it wouldn't require that much more technological advance to make them deployable.
"That's why I'm optimistic about this kind of bio-engineering. In terms of devices that may be useful to patients in their everyday lives I think that is plausible in the next 20 years."
-- With thanks to the Science Museum and the Dana Centre. NEURObotics... the future of thinking? runs until March 25.