Researchers at the University of Osaka, Japan, have revealed exciting advances in the external interpretation of a person’s mental activity.
Through a recent study, the team ensures that the meaning of an imagined image can be inferred from the pattern of a person’s brain activity.
Neural decoding of imagined images
When viewing an image in real life, whatever its context, the human brain captures this visual information, giving rise to certain detectable and measurable electrical activity in the brain. However, these brain patterns are not fixed. They can be changed by our attention and imagination in the moment.
“Attention is known to modulate neural representations of perceived images”says the study’s lead author, Ryohei Fukuma. “However, we didn’t know if imagining a different image could also change these representations.”he added.
To test this, the researchers developed a new technology by working with epilepsy patients who already had electrodes implanted in their brains to record and display electrocorticogram (graphic representation of brain impulses) readings of images they were imagining.
Patients were shown an image of the real-time reading and instructed to mentally imagine a different image representing a “landscape,” “human face,” or “word” (for example, thinking of a human face while looking various types of images) to control reading.
“The results clarified the relationship between brain activities when people look at images and when they imagine them”explains Takufumi Yanagisawa, lead author. “The electrocorticogram readings of the imaginary images were different from those elicited by the real images seen by the patients. They could also be modified to be even more distinct when patients receive real-time feedback.”.
The time needed to generate a very clear distinction between the image imagined and the image seen was different for imagining a “word” and a “landscape,” which might have something to do with the different parts of the brain involved in imagining these two concepts. . .
“Our findings suggest that an observer using this technology can infer a controlled readout image from the subject’s images.”Fukuma says.
With the precision with which this new technology displays images in the subject’s mind, a similar approach could be used to develop a communication device for severely paralyzed patients, such as those with amyotrophic lateral sclerosis. Some patients with this condition have used similar devices, which are based on motor control, which deteriorates faster than visual activity in the cerebral cortex, so an image-based device could be of great value for these purposes.
The detail of this research was published in an article in Communications Biology.
