July 23, 2009
Brain Scans Detect Which Of 8 Tasks Subjects Doing

By scanning brains of people doing 8 different tasks scientists can predict most of the time which mental task a person is working on.

New research by neuroscientists at UCLA and Rutgers University provides evidence that fMRI can be used in certain circumstances to determine what a person is thinking. At the same time, the research suggests that highly accurate "mind reading" using fMRI is still far from reality. The research is scheduled to be published in the October 2009 issue of the journal Psychological Science.

In the study, 130 healthy young adults had their brains scanned in an MRI scanner at UCLA's Ahmanson–Lovelace Brain Mapping Center while they performed one of eight mental tasks, including reading words aloud, saying whether pairs of words rhyme, counting the number of tones they heard, pressing buttons at certain cues and making monetary decisions. The scientists calculated how accurately they could tell from the fMRI brain scans which mental task each participant was engaged in.

"We take 129 of the subjects and apply a statistical tool to learn the differences among people doing these eight tasks, then we take the 130th person and try to tell which of the tasks this person was doing; we do that for every person," said lead study author Russell Poldrack, a professor of psychology who holds UCLA's Wendell Jeffrey and Bernice Wenzel Term Chair in Behavioral Neuroscience.

Just how many kinds of tasks can be distinguished? Could scientists detect the difference between someone reading a comedy versus someone reading a political tract that advocates for armed resurrection? My guess is that lots of different mental tasks will end up looking similar.

The scientists can guess the task being done 80% of the time.

"It turns out that we can predict quite well which of these eight tasks they are doing," he said. "If we were just guessing, we would get it right about 13 percent of the time. We get it right about 80 percent of the time with our statistical tool. It's not perfect, but it is quite good — but not nearly good enough to be admissible in court, for example.

This capability is far from a general mind reading tool.

"Our study suggests that the kinds of things that some people have talked about in terms of mind reading are probably still pretty far off," Poldrack said. "If we are only 80 percent accurate with eight very different thoughts and we want to figure out what you're thinking out of millions of possible thoughts, we're still very far away from achieving that."

But will fMRI ever make a good lie detector? Have you come across any fMRI lie detector studies?

Update: The researchers also find that a given function in the brain involves neural connections across multiple regions of the brain.

“You can’t just pinpoint a specific area of the brain, for example, and say that is the area responsible for our concept of self or that part is the source of our morality,” says Hanson. “It turns out the brain is much more complex and flexible than that. It has the ability to rearrange neural connections for different functions. By examining the pattern of neural connections, you can predict with a high degree of accuracy what mental processing task a person is doing.“

The findings open up the possibility of categorizing a multitude of mental tasks with their unique pattern of neural circuitry and also represent a potential first, early step in developing a means for identifying higher-level mental functions, such as 'lying' or abstract reasoning. They potentially also could pave the way for earlier diagnosis and better treatment of mental disorders, such as autism and schizophrenia, by offering a means for identifying very subtle abnormalities in brain activity and synchrony.

I'm curious to know whether people who do a function well (e.g. math) use more or less of the brain than people who do the same function poorly.

Share |      Randall Parker, 2009 July 23 07:28 AM  Brain Surveillance


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