Imagination and reality flow in opposite directions in the brain, according to a new study.
Researchers at the University of Wisconsin-Madison tracked electrical activity in the brains of people who alternately imagined scenes or watched videos.
“A really important problem in brain research is understanding how different parts of the brain are functionally linked. What areas are interacting? What is the direction of communication?” said Barry Van Veen, a UW-Madison professor of electrical and computer engineering. “We know brain doesn’t function as a set of independent areas, but as a network of specialized areas that collaborate,” Van Veen said.Researchers hope the work could lead to development of new tools to help untangle what happens in the brain during sleep and dreaming.
The study’s new methods could also help understand how the brain uses networks to encode short-term memory.
During imagination, the researchers found an increase in the flow of information from the parietal lobe of the brain to the occipital lobe – from a higher-order region that combines inputs from several of the senses out to a lower-order region.
In contrast, visual information taken in by the eyes tends to flow from the occipital lobe — which makes up much of the brain’s visual cortex — “up” to the parietal lobe.
The researchers said they approached the study as an opportunity to test the power of electroencephalography (EEG) – which uses sensors on the scalp to measure underlying electrical activity – to discriminate between different parts of the brain’s network.
To zero in on a set of target circuits, the researchers asked their subjects to watch short video clips before trying to replay the action from memory in their heads.
Others were asked to imagine traveling on a magic bicycle — focusing on the details of shapes, colours and textures — before watching a short video of silent nature scenes.
Using an algorithm Van Veen developed to parse the detailed EEG data, the researchers were able to compile strong evidence of the directional flow of information.
The research was published in the journal NeuroImage.
