Wednesday, February 18, 2009
Bloorview scientists demonstrate the ability to decode a person’s preference for one of two drinks with 80 per cent accuracy by measuring the intensity of near infrared light absorbed in brain tissue. Canada’s largest children’s rehabilitation hospital have developed a new technique that uses infrared light brain imaging to decode preference with the goal of ultimately opening the world of choice to children who can’t speak or move. “This is the first system that decodes preference naturally from spontaneous thoughts,” After teaching the computer to recognize the unique pattern of brain activity associated with preference for each subject, the researchers accurately predicted which drink the participants liked best 80 per cent of the time. Most brain-computer interfaces designed to read thoughts require training. Wearing a headband fitted with fibre-optics that emit light into the pre-frontal cortex of the brain, they were shown two drinks on a computer monitor, one after the other, and asked to make a mental decision about which they liked more. “When your brain is active, the oxygen in your blood increases and depending on the concentration, it absorbs more or less light.” Luu says. The brain is too complex to ever allow decoding of a person’s random thoughts. “However, if we limit the context limit the question and available answers, as we have with predicting preference – then mind reading becomes possible.“ Luu says. “In some people, their brains are more active when they don’t like something, and in some people they’re more active when they do like something.”
