Robert Knight is a neuroscientist who leads a research team at the University of California at Berkeley. His team and others at Berkeley have been doing a good bit of investigation into the ability to use fMRI to read peoples thoughts. The science revolves around the concept of programming computers to translate brain waves into words.
Some have postulated a wide variety of amazing applications. For example, you might be able to rewatch your dreams on a PC. Medical caregivers and loved ones might be able to communicate with patients in a coma. A person who has lost the ability to speak normally now could speak virtually. Although we have a long way to go before these benefits materialize, we are headed in that direction. And what about involuntary participation?
As with every technological breakthrough, we as a society owe it to ourselves and the generations that follow to understand the good and bad applications and implications. To use what we have discovered in an ethically appropriate manner is an indispensable calling from which we must not shrink. Those ethical dilemmas may be upon us sooner rather than later.
One of the neatest films that touches on the potential of this sort of situation is Minority Report (2002, Steven Spielberg). In that film, law enforcement is able to monitor peoples thoughts, thereby anticipating criminal behavior before it occurs. Armed with this information, law enforcement (the Precrime unit) intercepts would-be criminals before the crimes are committed.
I had a science teacher in seventh grade who frequently said, Todays science fiction is tomorrows science. I think that concept was once somewhat difficult to grasp. Today, it is becomingly increasingly obvious. Hopefully, the cognizance of ethical dilemmas will be too.