In “Mind Reading: Technology Turns Thought Into Action,” Jon Hamilton (National Public Radio, May 12, 2011) explains:
the experiment shows how the technology could help a very different sort of patient — someone paralyzed by a spinal injury or Lou Gehrig’s disease. ECoG could allow someone like that to operate a robotic arm with just their thoughts. The experiment also shows how many different areas of the brain get involved in things we take for granted, Schalk says. “Even for simple functions such as opening and closing the hand, there are many, many areas that contribute to the movement,” he says.
But some researchers are more enterprising than that:
… when a person simply thinks of a word instead of saying it, there are no muscle signals — just the activity in the parts of the brain involved in listening. “That seems to suggest that what imagined speech actually really is, it’s more like internally listening to your own voice,” Schalk says.
So he hopes to be able to read what people are thinking. Which means that prisoners under interrogation will have to develop an inner patter that sounds like the outer one.