Mind Reading is Here.(The Technologist)(brain activity)

Byline: Sharon Begley

crime investigators always have their ears open for information only a perpetrator could know. So imagine a detective asking a suspect about a killing, describing the crime scene to get the suspect to visualize the attack. The detective then asks him to envision the weapon. Pay dirt: his pattern of brain activity screams "hammer" as loud and clear as if he had blurted it out.

The prospect of reading thoughts by decoding brain-activity patterns is no longer difficult to imagine. "The new realization is that every thought is associated with a pattern of brain activity," says neuroscientist John-Dylan Haynes of the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany, "and you can train a computer to recognize the pattern associated with a particular thought."

Consider how quickly mind reading is advancing. Less than three years ago, it was a big deal when studies measured brain activity in people looking at a grating slanted either left or right; fMRI patterns in the visual cortex revealed which grating the volunteers saw. Last year Haynes and colleagues found that even intentions leave a telltale trace in the brain. When people thought about either adding two numbers or subtracting them, an fMRI scan of their prefrontal cortex detected activity characteristic of either.

Now research has broken the "content" barrier. Scientists at Carnegie Mellon University showed people drawings of five tools (hammer, drill and the like) and five dwellings (castle, igloo --) and asked them to think about each object's properties, uses and anything else that came to mind. Meanwhile, fMRI measured activity throughout each volunteer's brain. As the scientists report this month in the journal PLoS One, the activity pattern evoked by each object was so distinctive that the computer could tell with 78 percent ...