Dartmouth researchers have discovered new information about how and where imagination occurs in the human brain. Alexander Schlegel, a graduate student in psychological and brain sciences, recently led a study that focused how the brain manipulates mental images.
The researchers found that imagination occurs through a neural network or "mental workspace" in the brain and published their findings on the website of the Proceedings of the National Academy of Sciences earlier this week.
The study, "Network structure and dynamics of the mental workspace," was advised by psychology professor Peter Tse.
"What makes our species unique is being able to manipulate things in our mind and make them real as we imagined," Tse said. "We are closer to understanding the neural basis of imagination and this will."
Researchers looked at how brain activity differed depending on whether subjects were asked to visualize abstract shapes or imagine putting those shapes together into different combinations. They also asked study participants to imagine deconstructing patterns of shapes, among other tasks.
These exercises aimed to determine how brain activity, measured using an fMRI, differed depending on whether subjects were manipulating or maintaining imagery.
"What we were asking was, Can we do this analysis to distinguish patterns of brain activity that go along with constructing images from patterns of activity that go along with disassembling images," Schlegel said.
Participants in the final study included graduate students in the department as well as some undergraduates. The 15 participants underwent hour-long training sessions, which involved completing complex tasks, and return for fMRI screenings the following day.
Schlegel said the findings support the idea of the brain as a "global workspace," where many areas of the brain are simultaneously active.
"We found lots of different areas that were involved, but at this point it's difficult to tell what exactly the roles of each of these areas is," Schlegel said.
Scholars have debated whether the brain is a global workspace as opposed to more localized, neural correlates of consciousness. The study provided direct evidence that multiple areas of the brain communicate with each other.
Schlegel hopes the study will inspire further study of brain activity and cautioned that looking too narrowly may "miss the nature of these more complex kind of behaviors that require distributive networks working together."
Tse and Schlegel have long been interested in the "flexible cognitive abilities" that distinguish humans from other animals and have worked on the study since 2011.
Schlegel is also curious about the brain's ability to construct novel images and recall previous memories.
"That seems to be behind what makes humans different, to have this very rich mental playground where we can play around with symbols, images, and other ideas," he said. "It seems very effortless, but something in your brain must be constructing that image."
Previous studies have also looked at higher-level cognitive functions, such as analogy, creative thought and working memory, but they mostly focused on the frontal parietal network, Schlegel said.
While the study consisted of a visual task, Schlegel has considered adding an auditory task in the future.
"It's very easy to find where in the brain something is happening, but that doesn't tell you necessarily how that's happening," he said. "If we want to understand mechanisms behind these abilities in humans then we need to develop new tools."
Tse is optimistic about the study's findings.
"The better we can understand what makes us unique, the more we will understand not only ourselves, but how we can better ourselves and become more imaginative to good ends," Tse said.
He said that he hopes that this understanding might eventually allow researchers to understand how to facilitate creativity and imagination through education.
Jorge Bonilla contributed reporting.
