RESEARCHERS have taken a leap into the world of science fiction by creating a computer program that uncovers memories.
Scientists used the "mind-reading" software to tell which of three film scenes their volunteers were thinking about simply by analysing their brain activity.
The research illuminates mechanisms of memory which are still not clearly understood.
It could also lead to better ways of helping people who suffer memory loss as a result of injury or old age.
The study was carried out at the Wellcome Trust Centre for Neuroimaging at University College London, where the same team last year showed how "spatial" memories relating to a person's location could be "read".
The new work goes a big step further by tapping into "episodic" memories – the complex recollections of everyday events that include actions and feelings.
Ten participants were first asked to watch three seven-second movie clips and memorise what they saw.
The film extracts were simple and depicted ordinary scenes in a typical urban street, including a woman drinking coffee from a paper cup and another actress posting a letter.
Volunteers then recalled each clip in turn while having their brains scanned by a functional magnetic resonance imaging (fMRI) machine. The scanner uses a magnetic field and radio waves to identify regions of heightened brain activity.
Professor Eleanor Maguire, who led the researchers, said she wanted to advance science and help patients rather than read minds.
"We still need to understand how the memory system works, then we can really start to help patients who have memory problems," she said.
"It's very hard to say whether it will ever really be possible to see what people are thinking. Obviously from the way we are doing this research the answer is no, but that doesn't mean other techniques won't evolve."