The human brain is remarkably adept at juggling different kinds of information, allowing us to switch rapidly between tasks and adapt our behavior as circumstances change. A new study by MIT neuroscientists takes a closer look at how the brain accomplishes this, providing evidence for flexible neural modules that may help support this cognitive versatility.

Using mice, scientists found that a group of neurons in the prefrontal cortex could switch between retaining sensory information and maintaining an action plan in working memory.

“We found that the brain doesn’t dedicate a separate group of neurons for every type of information,” says Yuma Osako, an MIT postdoc and the lead author of the new study. “Instead, it uses the same populations of neurons to perform the same computation on different kinds of information, which means the same subset of neurons can hold both an action and a sensory stimulus in working memory,”

The findings also lend support to a longstanding theory known as compositionality—the idea that cognition can be constructed by combining and reusing neural components.

“One of the solutions that’s always been proposed has been this idea of compositionality — that you can take pieces of cognition that perform part of a task and reuse them in another task,” says Timothy Buschman, a professor at the Princeton Neuroscience Institute, and the senior author of the paper, in a statement. 

Another way to see this is to view it as “cognitive Legos,” Buschman suggests. Instead of building a new neural circuit when a new task starts, the brain reuses existing circuits and combines them in different ways.

The Test 

To see how this neural network operates, the scientists trained mice to compare two tones and respond depending on whether the sounds matched. As the mice performed the tasks, the scientists recorded electrical activity from thousands of neurons. 

“When mice do tasks that test whether memory computations can be reused, the answer is they are,” notes Mriganka Sur, the Newton Professor of Neuroscience at MIT’s Picower Institute for Learning and Memory. “There are subspaces of functional activity in the prefrontal cortex that can be the substrate of mixing and matching toward flexible cognition.”

Two important components of the task allowed the researchers to examine how different kinds of information were maintained. First, the mice had to remember the initial tone for a short period. They then had to retain their decision and form an action plan.

In the parietal cortex, neurons were dedicated to storing information about the tone. However, researchers found something different in the prefrontal cortex: a specific group of neurons could switch roles.

During one stage of the task, the circuit helped maintain a sensory memory. During another, the same population was involved in maintaining an action plan. This flexibility may help explain how a finite number of neurons can support an enormous range of behaviors.

“Our everyday life requires us to temporarily hold many different kinds of information. One big question is how the brain can represent an unlimited variability of information using only a finite number of neurons,” Osako says.

The researchers view these reusable neural circuits as potential building blocks for flexible cognition. More broadly, the findings suggest that the brain may be less like a machine filled with components dedicated to individual tasks and more like an interconnected system that continually repurposes its existing neural resources.

The recent study appeared in the journal Nature.

Chrissy Newton is a PR professional and the founder of VOCAB Communications. She currently appears on The Discovery Channel and Max and hosts the Rebelliously Curious podcast, which can be found on YouTube and on all audio podcast streaming platforms. Follow her on X: @ChrissyNewton, Instagram: @BeingChrissyNewton, and chrissynewton.com. To contact Chrissy with a story, please email chrissy @ thedebrief.org.

Scientists have uncovered new details about how the brain’s “information hub” responds to uncertainty, revealing a remarkably flexible system that rapidly changes how it communicates with other brain regions as we make decisions.

Every second of our lives, the human brain sorts through enormous amounts of information. From remembering a driving route and handling daily tasks to making decisions, the brain must continually determine what information matters and how to respond. Researchers at the University of Iowa wanted to better understand how the human brain manages and processes this information and found that it may be more flexible than previously thought.

At the center of this sorting process is an area of the brain known as the frontoparietal cortex. This region supports decision-making and behavioral control and can function as a kind of “information hub” for the brain.

The Study 

Using MRI scans, behavioral experiments, and computational modeling, researchers took a deeper look at how the frontoparietal cortex responds when people are uncertain about what they should do next.

“That’s the main contribution,” says Kai Hwang, associate professor in the Department of Psychological and Brain Sciences and the study’s corresponding author, in a statement. 

“Our study shows in more detail how the frontoparietal cortex operates — what kind of information it extracts from other systems and how it uses its connectivity pattern to integrate information that is coming in from different areas of the brain,” Hwang adds. 

The research team recruited 38 participants between the ages of 18 and 35 and had each person learn associations between combinations of colors, faces, and scenes and particular actions—for example, pressing a button with the index or middle finger of either hand. The researchers then intentionally changed those associations.

When an action or rule changes, the brain has to determine what went wrong.

Did the situation change? Was the information unclear? Or did the person simply make a mistake? This uncertainty allowed researchers to observe how the brain’s “information hub” responds under different circumstances.

“It’s like where other areas of the brain don’t have all the information, so they send what they have to the frontoparietal cortex for guidance,” Hwang explains.

The results from the team’s research suggest the frontoparietal cortex does more than become more active when a task becomes difficult. Instead, the region changes how it communicates with other brain regions. This also depends on what information is needed at different decision-making stages. 

Hwang notes, “If they always get it right, they know they’ve made the correct association, but once they start doing it wrong, they will have to guess, ‘Oh, did the context change, or did I not see the color clearly?’ That creates uncertainty.” 

Your Brain Has an Air Traffic Controller

Hwang describes the brain’s “information hub” as a system that gathers information from different regions, determines what is relevant, and integrates those signals into a broader picture. One way to think of this function is as an air traffic controller, monitoring incoming information and adjusting communications as circumstances change.

“These are situations where people struggle with regulating their behavior. That, to me, is an integration problem. If that integration function is not working properly, then that could very likely mean they didn’t use the right context to regulate their behavior,” Hwang adds.

The study does not address how neurodiversity might affect this information-sorting process, although the findings could provide a foundation for researchers to investigate that question.

“It remains an open question how neurodiversity might affect frontoparietal integration. It is a very interesting question that, as far as I know, has not been studied directly, so I don’t have a definitive answer. One of our goals in conducting this study is to lay the foundation for future clinical investigations,” Hwang tells The Debrief in an email.

The findings suggest that the frontoparietal cortex can rapidly integrate and update information as circumstances change. Understanding this flexibility could eventually improve researchers’ understanding of neurological and psychiatric conditions involving behavioral regulation and decision-making. In particular, studying these communication patterns could help inform future investigations of conditions such as ADHD and schizophrenia, in which behavioral regulation and the use of contextual information can be impaired.

The new research was published in the Journal of Neuroscience.

Chrissy Newton is a PR professional and the founder of VOCAB Communications. She currently appears on The Discovery Channel and Max and hosts the Rebelliously Curious podcast, which can be found on YouTube and on all audio podcast streaming platforms. Follow her on X: @ChrissyNewton, Instagram: @BeingChrissyNewton, and chrissynewton.com. To contact Chrissy with a story, please email chrissy @ thedebrief.org.