My Wife and My Mother-in-Law is a famous ambiguous optical illusion in which a woman appears to be both young and old as your brain flips back and forth between two conflicting perceptions. Images like this illustrate how your brain can play tricks on your neural circuitry as your mind struggles to interpret perceptions of reality.
As you look at the image above, what do you see first? When you feel your visual perception shift from the "wife" to the "mother-in-law" can you also identify an "a-ha" millisecond in which it feels like your brain has changed gears and the perception of reality is traveling on a different brain pathway?
In a fascinating new study, researchers were able to identify this phenomena under slightly different circumstances in a laboratory. The October 2014 study, “Reversal of Cortical Information Flow During Visual Imagery as Compared to Visual Perception," was published in the journal NeuroImage.
Barry Van Veen—a UW-Madison professor of electrical and computer engineering—performed this research in collaboration with Giulio Tononi, a UW-Madison psychiatry professor and neuroscientist, Daniela Dentico, a scientist at UW-Madison's Waisman Center, and collaborators from the University of Liege in Belgium.
The role of bottom-up and top-down connections during visual perception and the formation of mental images was examined by analyzing high-density EEG recordings and other state-of-the-art methods.
The researchers hope that these findings could lead to the development of new tools to help Tononi deconstruct what is happening in our brains during sleep and dreaming. Van Veen hopes to apply the study's new methods to understand how the brain uses networks to encode short-term memory.
To identify changes in the flow of information during daydreaming versus watching a movie, the researchers used two different methods. In the first experiment they asked their subjects to watch short video clips and then replay the action in their mind's eye using their imagination.
In the second experimient, subjects were asked to imagine riding a "magic bicycle" and to conjure up imaginery details of shapes, colors and textures they saw in the world around them, then they were asked to watch a short video containing scenes of nature.
Visual information taken in by the eyes when watching a video flows directly to the occipital lobe and is then sent "up" to the parietal lobe.
The researchers at the University of Wisconsin-Madison identified that electrical activity in specific brain regions changes direction depending on whether subjects were asked to imagine a scene or watch a video of that scene.
During imagination, the researchers identified an increase in the flow of information from the parietal lobe of the brain down to the occipital lobe. This is a type of "top-down" processing from a higher-order region to what most consider a lower-order region.
In a press release, Barry Van Veen said, "A really important problem in brain research is understanding how different parts of the brain are functionally connected. What areas are interacting? What is the direction of communication? We know that the brain does not function as a set of independent areas, but as a network of specialized areas that collaborate."
Using a revolutionary technique, the researchers were able to quantify the directionality of signal flow during perception of movie clips versus replaying the clips in their imagination.
The study revealed an increased top-down signal flow in during mental imagery as compared to visual perception. These results are the first direct demonstration of a reversal of the predominant direction of cortical signal flow during mental imagery as compared to perception.
Van Veen concluded, "There seems to be a lot in our brains and animal brains that is directional, that neural signals move in a particular direction, then stop, and start somewhere else. I think this is really a new theme that had not been explored."
Illustrations of Information Flowing Differently During Visual Perception
As you can see by looking at this ink drawing from 1892, perceptions of reality can be subjective. What animal did you first see when you looked at this sketch?
Does your brain have trouble simultaneously seeing both the duck and the rabbit while looking at the picture? Now close your eyes and imagine the image. Is it easier to loosely flip back and forth between the two in your mind's eye?
This image was made famous by Ludwig Wittgenstein, who included it in his Philosophical Investigations as a means of illustrating choices you can make when observing the world around you.
In the 1820s, Johannes Purkinje wrote two influential books on the subjectivity of visual perceptions. Purkinje believed that “visual illusions reveal visual truths”.
I believe that visual realities can also create misperceptions if you are too rigid in your viewpoint of how the world appears from a "top-down" or "bottom-up" perspective. Researchers are beginning to understand why flipping between strict executive function to daydreaming or mind-wandering can improve creative thinking and cognitive function by optimizing the flow of information between various brain regions.
Conclusion: Optimizing Information Flow In Both Directions and Between All Brain Regions Throughout the Day Is Key to Creativity and Cognitive Function
If you tend to overthink and be hyper-analytical all the time, current research shows that you might want to "unclamp" your executive function throughout the day and let your mind wander more. Conversely, if you tend to be spacey or always daydreaming, your mind and brain will benefit by consciously making an effort to dial-in your focus and force your mind to wander less at some point throughout the day.
It's important to stay cognizant and vigilant about constantly mixing up your explanatory style and perceptions of the world. This will prevent the neural networks of you mind and brain from getting stuck in a rut that blocks a healthy flow of information in all directions.
The key appears to be surfing your individual tendecies of thinking to find your individual sweet spot. You can do this by regularly flipping from linear to divergent thinking and using both your imagination and pragmatism throughout every day. Making this a habit wil engage every nook and cranny of your brain from different angles and maximize the potential of your brain and mind.
The new research from Tononi et al offers exciting new connections between information flow, cognitive function and creativity. Although the new study doesn't specifically include the cerebellum or other brain regions beyond the occipital or parietal regions, I have a gut instinct that more exciting findings are around the corner. Stay tuned!
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Photo Credits: Wikimedia Commons