Scientists Extract Images Directly from Brain
Researchers from Japan’s ATR Computational Neuroscience Laboratories have developed new brain analysis technology that can reconstruct the images inside a person’s mind and display them on a computer monitor, it was announced on December 11 2008. According to the researchers, further development of the technology may soon make it possible to view other people’s dreams while they sleep.
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 black-and-white 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.
“These results are a breakthrough in terms of understanding brain activity,” says Dr. Cheng. “In as little as 10 years, advances in this field of research may make it possible to read a person’s thoughts with some degree of accuracy.”
The researchers suggest a future version of this technology could be applied in the fields of art and design — particularly if it becomes possible to quickly and accurately access images existing inside an artist’s head. The technology might also lead to new treatments for conditions such as psychiatric disorders involving hallucinations, by providing doctors a direct window into the mind of the patient.
ATR chief researcher Yukiyasu Kamitani says, “This technology can also be applied to senses other than vision. In the future, it may also become possible to read feelings and complicated emotional states.”
The research results appear in the December 11 issue of US science journal Neuron:
Perceptual experience consists of an enormous number of possible states. Previous fMRI studies have predicted a perceptual state by classifying brain activity into prespecified categories. Constraint-free visual image reconstruction is more challenging, as it is impractical to specify brain activity for all possible images. In this study, we reconstructed visual images by combining local image bases of multiple scales, whose contrasts were independently decoded from fMRI activity by automatically selecting relevant voxels and exploiting their correlated patterns. Binary-contrast, 10 10-patch images (2100 possible states) were accurately reconstructed without any image prior on a single trial or volume basis by measuring brain activity only for several hundred random images. Reconstruction was also used to identify the presented image among millions of candidates. The results suggest that our approach provides an effective means to read out complex perceptual states from brain activity while discovering information representation in multivoxel patterns.