When we perceive images in real life, our brains take in the visual information in a way that can be detected by a technique called electrocorticography, which records patterns of electrical activity in the brain. However, according to a new study led by the Osaka University, these patterns are not set in stone, but can be changed by what we are paying attention to or imagining at the time.
“Attention is known to modulate neural representations of perceived images,” said study lead author Ryohei Fukuma, an assistant professor of Neuroscience at the Osaka University. “However, we didn’t know whether imagining a different image could also change these representations.”
In order to test this, Professor Fukuma and his colleagues worked with 17 patients with epilepsy who already had electrodes implanted in their brains to record and display electrocorticogram readouts of what they were imagining. The patients were shown an image of the real-time readout and asked to imagine a different thing, such as a landscape, a word, and a human face.
“The results clarified the relationship between brain activities when people look at images versus when they imagine them,” explained study senior author Takufumi Yanagisawa, an expert in brain-machine interface at Osaka. “The electrocorticogram readouts of the imagined images were distinct from those provoked by the actual images viewed by the patients. They could also be modified to be even more distinct when the patients received real-time feedback.”
The time needed to generate clear distinctions between viewed and imagined images was different for imagining a word and a landscape, suggesting that different parts of the brain are responsible for imagining these two concepts.
Considering the accuracy with which this new technology can display images that exist within a subject’s mind, a similar approach could be used to develop communication tools for paralyzed people, such as those with amyotrophic lateral sclerosis. While similar devises that rely on motor control already exist for patients with such conditions, they degenerate faster than visual cortical activity, so an imagery-based device could be much more useful and reliable.
The study is published in the journal Communications Biology.
By Andrei Ionescu, Earth.com Staff Writer