How owls could help scientists understand ADHD
A team at Johns Hopkins University in Baltimore is studying barn owls in an attempt to understand the brain circuits that control attention.
While owls are highly focused predatory birds, most people with ADHD are not.
The team’s major goal is to figure out what goes wrong in the brains of people with attention problems, including ADHD.
“We think we have the beginnings of an answer,” says Shreesh Mysore, an assistant professor who oversees the owl lab at Hopkins. He suspects the answer involves an ancient brain area with special cells that tell us what to ignore.
As a demonstration, Mysore explains his hypothesis from one of the owl rooms in his basement lab. An owl, sits perched on his arm, clearly distraught by a new visitor.
Mysore covers the bird’s eyes with his free hand and hugs the animal to his chest.
The owl, no longer able to focus on the movements of his visitors, goes quiet.
When it comes to paying attention, barn owls have a lot in common with people, Mysore says.
“Essentially, a brain decides at any instant, what is the most important piece of information for behavior or survival? And that is the piece of information that gets attended to, that drives behavior.”
For a hungry owl, important information might be the sound of a wood mouse scampering through the grass. For a human parent, it might be the cry of a baby in the next room.
In either case, hearing the sound causes a distinct response in the brain.
“Mysore explains that when the brain decides to focus on something, it’s also shutting out everything that’s not relevant at that moment in time.
But how does the brain actually help you ignore stuff that’s not important for you?
Mysore believes answering that question could help people whose brains are vulnerable to distractions. That includes not only people with ADHD, but also many with autism, schizophrenia, and even Parkinson’s disease.
The problem is that scientists still don’t know much about the brain’s system for suppressing distractions and it’s extremely complex to try study a human brain. However, owls offer a good substitute as they’re incredibly focused birds that need to physically turn their heads in order to fixate on whatever’s caught their attention.
The lab is doing experiments in which an owl must decide whether to focus on something it hears or something it sees. For example, an owl might be listening to bursts of noise coming through special earphones while a computer monitor shows an object approaching quickly.
That sets up a competition between these stimuli in the midbrain, an ancient part of the brainstem that can be found in animals ranging from reptiles to humans.
“When we’re presenting these stimuli, we’re measuring activity in key areas in the midbrain to try and figure out how that stimulus competition is actually being implemented or carried out by neurons in the brain,” Mysore says.
Several years ago, Mysore and Eric Knudsen, a professor at Stanford, identified a system in the owl midbrain that appears to control which stimulus to ignore. The results suggested there are precise neurons that tell a brain when to start ignoring sights and sounds that aren’t important at that moment.
That could be critical to understanding why people with attention disorders have so much trouble ignoring distractions, Mysore says.
The lab’s next challenge is to show that mice, and eventually humans, also have these special neurons. If they do it could provide a new target for treatments aimed at a wide range of disorders that affect attention.
