Imagination And Reality Flow In Opposite Directions In The Brain
Picture you’re going skydiving. Even if you’ve never done it, there’s probably some part of your imagination that can visualize what it feels like to leap from an airplane, tumble through the clouds, and, thanks to your trusty parachute, calmly waft back to Earth.
New research suggests that what happens in your brain while you imagine that experience is the direct opposite of what goes on when you actually do it. Leaping from the airplane, tumbling through the clouds, and wafting back to Earth — the experiences all hit your sensory organs and travel to your brain, where they are processed as abstract thoughts. Scientists believe understanding more about the difference between the two phenomena could help unlock the nature behind some of the brain’s most complex neural networks.
“A really important problem in brain research is understanding how different parts of the brain are functionally connected,” said Barry Van Veen, a University of Wisconsin-Madison professor of electrical and computer engineering, in a statement. “What areas are interacting?”
Van Veen is the senior author of a recent study into these cognitive interactions. He and a team of engineers and neuroscientists fitted a group of people with a device that reads electrical activity along the scalp, using technology known as electroencephalography, or EEG. First, half of the people watched a series of short video clips, before being told to replay the clips in their heads. The other group was told to imagine riding a magical bicycle — taking great care to fill in the small details of texture, speed, and color — before watching a series of videos of silent nature scenes.
The two conditions let Van Veen and his team track the flow of information as it entered and left the brain. They saw some stark differences. In the first scenario, visual information traveled to the brain’s occipital lobe, which handles most incoming visual stimuli, and got transferred “up” to the parietal lobe, where higher-order functions take place. But in the second scenario, the flow traveled in the opposite direction. Information traveled from the parietal lobe down to the occipital lobe, as complex mental images got reorganized as concrete pictures.
“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,” Van Veen said. “I think this is really a new theme that had not been explored.”
If asked, a lot of people would probably agree the findings legitimize their personal experience. When we think about doing a particular thing, like eating a giant steak or diving into a swimming pool, our brains sort through the filing cabinets of our consolidated memories for experiences that coincide with the desired behavior. Mentally, we connect the dots and visualize the action, to the point where it actually feels real. The same thing happens in reverse. Each time we actually do eat a giant steak or dive into a swimming pool, the flavor of the food and the chill of the water get sent to our brains as packets of data to be analyzed.
Confirming what people experience day to day isn’t exactly the point of the research, even if it is a perk. Van Veen has hopes of using the findings to understand how the brain encodes short-term memory. Some of his co-authors have other plans, such as bringing the findings to areas of sleep and dreaming research and developing new tools to measure how information flows. So even when we’re asleep, with visions of leaping out of airplanes before wafting down to Earth, scientists can know what our brains are up to.
Source: Dentico D, Cheung B, Chang JY, et al. Reversal of cortical information flow during visual imagery as compared to visual perception. NeuroImage. 2014.