Watching the brain predicting the future
According to this news release, a team of neuroscientists at Washington University School of Medicine in St. Louis (WUSTL) has discovered that it is possible to accurately predict if game players will succeed or fail by scanning their brains. Before starting the game, they scanned the volunteers with functional brain imaging and they found their future choices in 70 percent of the tests. The researchers conclude that "visual perception not only depends on the quality of sensory signals but also on the variability of internal signals."
This study was conducted the members of the Attention and Brain Recovery Lab, and in particular, Maurizio Corbetta, professor of neurology, and Ayelet Sapir, a postdoctoral research associate in neurology.
The figure below illustrates the research themes of these neuroscientists, which are to understand the neural basis of human cognition, in particular vision and attention. "Areas of the human brain involved in these processes are visualized in vivo in normal volunteers using functional magnetic resonance imaging (fMRI). These methods allow us to record hemodynamic changes in the brain, that are indirectly related to neuronal activity, during normal behavior." (Credit for image and caption: Maurizio Corbetta, WUSTL).
Now, what was the game and how these researchers run their experiments?
Eleven seconds before volunteers played the game -- discriminating the direction of a field of moving dots -- scientists showed them a hint: an arrow pointing to where the moving dots were likely to appear. The dots were visible only for one-fifth of a second and therefore were easy to miss if a subject was not paying attention to the right area.
After the hint and prior to the appearance of the moving dots, researchers scanned the volunteers with functional brain imaging, which reveals increases in blood flow to different brain areas indicative of increased activity in those regions. Based on brain activity patterns that reflected whether the subjects used the hint or not, scientists found they could frequently predict whether a volunteer's response would be right or wrong before the volunteers even had a chance to try to see the dots.
And here are some of the conclusions of the researchers.
Sapir and her colleagues concluded that volunteers don't use the hint the same way every trial. One speculation was that some of the brain signals they detected might be signs of the brain's struggle to cope with an ambiguity built into the test: the volunteers knew the hint was only accurate 80 percent of the time.
"Whether the hint is accurate or not was determined by the computer's random number generator, and the volunteers were not going to be able to beat that," says coauthor Giovanni d'Avossa, M.D., an instructor in neurology. "But regardless of how hopeless it was to try to outguess the computer, some of our data suggest that the brain may still have been trying to do just that: to figure out a formula or a rule based upon which it could predict whether a hint was valid and should be trusted."
The results of this research were published online in the 'Proceedings of the National Academy of Sciences' under the title "Brain signals for spatial attention predict performance in a motion discrimination task" on November 23, 2005. Here is a link to the abstract.
The team of neuroscientists has written a large number of papers on the subject of brain and attention. Among these publications, you should read an article published by 'Cerebral Cortex,' "Two Attentional Processes in the Parietal Lobe" (Vol. 12, No. 11, 1124-1131, November 2002).
Sources: Michael Purdy, Washington University School of Medicine in St. Louis news release, November 29, 2005; and various web sites
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