A cyclist is pedaling down the street. Signs, trees and fire hydrants whip by. As the rider bikes along, their brain takes in information from what they’ve perceived but can no longer see. There are all sorts of info — the color, shape and text on signs, for example. The cyclist’s brain sorts through it all and selects what is most important. Based on that, the biker takes the correct turn and continues on. 

Freek van Ede uses a lot of bicycling metaphors. This makes sense for a researcher in the Netherlands. Bicycling is very popular there. A cognitive neuroscientist at Vrije Universiteit Amsterdam, van Ede studies attention.  

His focus is not on external attention. That’s what someone is looking at or attending to in the moment. Instead, van Ede is trying to understand internal attention. This is how the brain takes all the information coming in from the environment and selects exactly what it needs to guide future behavior. 

Van Ede thinks of the brain as an organ of anticipation. Think about when you’re riding a bike. You use your recent experience to guide upcoming actions. This is a process our brains are performing all the time when we are awake. “It’s really at the core of cognition,” van Ede says.  

This process depends on working memory. That’s the ability to store information short-term. But the process also requires attention. We have to select from all that stored information to translate it into action. “It’s really a fundamental process. And I think that’s what appeals to me about it. And I want to understand how it works,” van Ede says. 

Van Ede hopes to combine studies of working memory and attention to get a better understanding of thought as a whole. Along the way, he and his colleagues have developed new techniques to measure exactly how people might be processing the world around them.   

 By using electroencephalography, van Ede’s lab can “watch” how the brains of study participants react to the world in real time. 
Peter Valckx/Vrije Universiteit Amsterdam

Paying attention to time 

Van Ede attended Utrecht University in the Netherlands for his undergraduate studies. There, he was thrilled to find out that he could continue studying and learning for his whole career. All he had to do was become a scientist.  

He especially recalls what drew him to his eventual postdoctoral mentor, Kia Nobre. She is now at Yale University in New Haven, Conn. Van Ede remembers “just reading her studies and thinking, ‘Hey, there’s somebody doing things a bit different than most people do it.’” 

At the time, most cognitive neuroscientists were looking at attention in terms of 3-D space. An example is an experiment where blocks are placed in different places on a screen. A person would then be asked to select among the blocks. Nobre, however, was interested in how time might play a role. 

Van Ede began thinking about the question of time, too. After all, we don’t spend our lives frozen in time, responding to objects on a screen. We move through the world and see things in sequence. “When we perform a dance, or even ride a bike or anything we do,” van Ede says, “our movements are carefully orchestrated in time.” 

Getting a more real-world picture means measuring brain activity in real time. This is why van Ede uses electroencephalography, or EEG. “It’s kind of remarkable that we can put an electrode on somebody’s skull … and we can measure electrical activity emitted by the brain,” he says. “That means we can measure brain activity as it’s happening.” People can also move freely in EEG caps. That means they can encounter the world in a more natural way while being studied. 

The eyes have it 

At first, van Ede and his colleagues were pairing EEG with eye-tracking data. This was a way to ensure participants looked at what they were told to. “One day, I decided to actually dive in and explore the eye data,” van Ede says. “Out of curiosity, really.”  

He found that when someone was asked to recall something about an object that had been on the screen, their gaze flicked toward where the object had been. They did this even though the object was no longer there. 

Freek van Ede scans a participant’s eyes, looking for microsaccades. These are tiny, unconscious eye movements that reflect where the brain’s attention lies.Peter Valckx/Vrije Universiteit Amsterdam

That flicking was detectable as microsaccades. These are tiny, unconscious movements that your eyes make multiple times per second. These movements are invisible to the naked eye. And they are smaller than the ones that your eyes make two to three times per second to take in a visual scene. 

When study participants shifted their attention to focus on where an object had been, the microsaccades were pulled in the direction of that attention shift. “We soon realized this discovery also opened new opportunities for ‘tracking the mind’s eye,’” van Ede says. And that let his team decipher what information the brain is using to plan future action. 

His lab has used the technique to show that when preparing for the future, the brain doesn’t wait to make a plan. Instead, the brain plans possible actions as each piece of information comes in. 

Van Ede “seems to be very good at coming up with new twists on older designs” for a task, says Tobias Egner. He’s a cognitive neuroscientist at Duke University in Durham, N.C.  

By putting participants in a virtual world, Freek van Ede can learn how brains select which information is important for upcoming actions.Peter Valckx/Vrije Universiteit Amsterdam

A basic understanding of how the brain plans actions could someday help us understand memory disorders or attention problems. But that’s not the primary driver for van Ede. What he and his team choose to study is “a little bit based on our intuition, even what is interesting,” van Ede says. 

In recent work, van Ede and colleagues are looking for signs of the repeated shifts of microsaccades while people play in virtual reality. Study participants work inside a virtual world where objects flow past, like signs would on a street. Van Ede tracks the tiny eye movements to see how people’s brains are using the information they recently encountered to make a plan. It’s one step closer to biking through the streets of Amsterdam.