12 Dec 2008
The scientists were able to reconstruct various
images viewed by a
person by analyzing changes in their cerebral blood flow. Using a
functional magnetic resonance imaging (fMRI) machine, the researchers
first mapped the blood flow changes that occurred in the cerebral
visual cortex as subjects viewed various images held in front of their
eyes. Subjects were shown 400 random 10 x 10 pixel black-and-white
images for a period of 12 seconds each. While the fMRI machine
monitored the changes in brain activity, a computer crunched the data
and learned to associate the various changes in brain activity with the
different image designs.
Then, when the test subjects were shown a completely
new set of
images, such as the letters N-E-U-R-O-N, the system was able to
reconstruct and display what the test subjects were viewing based
solely on their brain activity.
For now, the system is only able to reproduce simple
images. But Dr. Kang Cheng, a researcher from the RIKEN Brain Science
Institute, suggests that improving the measurement accuracy will make
it possible to reproduce images in color.