Optical brain imaging decodes preference

Researchers at Canada’s largest children’s rehabilitation hospital, namely Bloorview Kids Rehab, have developed a 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. In a study published this month in The Journal of Neural Engineering, 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.
Most brain-computer interfaces designed to read thoughts require training. For example, in order to indicate yes to a question, the subjects need to do an unrelated mental task, such as singing a song in their head. The nine adults in the study received no training. Prior to the study they rated eight drinks on a scale of one to five. 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 the brain is active, the oxygen in the blood increases and, depending on the concentration, it absorbs more or less light. In some people the brain is more active when they don’t like something, and in some people it’s more active when they do like something. After allowing the computer to recognise the unique pattern of brain activity associated with preference for each subject in the study, the researchers accurately predicted which drink the participants liked best 80 per cent of the time. In future, a portable, near-infrared sensor that rests on the forehead and relies on wireless technology could be developed, opening up the world of choice to children who can’t speak or move.

www.iop.org/EJ/abstract/1741-2552/6/1/016003