What helps the brain tune out distractions and stay focused on what truly matters? Scientists at Johns Hopkins University believe they may have found part of the answer in one of the brain's oldest regions. The newly identified cells appear to function as a natural filtering system, helping animals ignore competing signals and concentrate on important information. The discovery could eventually reshape how researchers understand attention disorders such as ADHD, as quoted in a report by Science Daily.
The findings, published in Nature Communications, suggest that this mechanism is shared across vertebrates, including humans.
Why do animals need this focus system?
For years, many researchers believed that the prefrontal cortex was the brain's primary center for attention. But a new study from Johns Hopkins University is challenging that idea by pointing to a much older system buried deep within the brain. The research reveals a set of ancient brain cells that appear to act as a natural distraction filter, allowing animals to focus on what matters most while tuning out competing information.
Every day, humans and animals are faced with countless sensory signals. The ability to prioritize one piece of information over another, known as selective spatial attention, makes it possible to follow a conversation in a crowded room or recognize a familiar face in a busy environment, as quoted in a report by Science Daily.
According to the researchers, difficulties with this process are often linked to conditions such as ADHD and autism.
The federally funded study, recently published in Nature Communications and selected as an editorial highlight, examined how this ability might be controlled by parts of the brain that evolved hundreds of millions of years ago.
Lead author Ninad Kothari explained the puzzle scientists have long faced.
"If we really go back in evolution, for hundreds of millions of years, birds have had this ability, fish have had this ability. And they do not typically have a highly developed prefrontal cortex, so how does the brain solve this problem?" he said.
"We were able to identify an evolutionarily old region in the brainstem which affords this ability."
What happened when the neurons were switched off?
The team discovered a network of inhibitory neurons in the brainstem that appears to regulate attention in mice. Similar cells are found in birds, fish and other vertebrates, suggesting the mechanism may be deeply rooted in evolutionary history.
To study their function, researchers designed an attention task resembling experiments commonly used in humans. Mice had to focus on visual information directly in front of them while ignoring distracting cues on either side.
The animals performed successfully until scientists temporarily disabled the neurons. "When we inactivate these neurons, the mice become hyper distractable," Kothari said.
Researchers ruled out problems with vision or movement. Instead, the results showed that the animals specifically lost the ability to compare competing signals and identify which one deserved attention.
Senior author Shreesh Mysore described the system as a built-in selection engine.
"The only thing impaired was their ability to take the competing pieces of information, compare them, and pay attention to the location with the most important information," Mysore said. "This part of the brain is like an attentional selection engine. It helps solve the question: 'What is most important information I should pay attention to right now?'"
He also noted similarities to symptoms commonly associated with ADHD.
"A hallmark of ADHD is that even faint distractors draw attention away -- and that's exactly what we see here when these neurons are silenced," Mysore said.
"But the very next day, when the neurons are turned back on, the same animal can ignore distractors again, even very strong ones."
Could humans have the same brain mechanism?
The researchers believe the answer may well be yes. According to Mysore, evidence gathered so far suggests that humans possess these same ancient neurons. The next challenge is determining whether they perform an identical role in directing attention.
"All the evidence to date suggests that these neurons exist in humans too,"he said. "But are they responsible for selective spatial attention in humans? An exciting hypothesis is that they play a crucial role."
Future investigations could examine whether these cells behave differently in people with ADHD or autism. If so, scientists may eventually be able to design therapies that target this specific attention network rather than broader regions of the brain.
The findings offer a powerful reminder that some of the brain's most sophisticated abilities may rely on structures that have been quietly serving vertebrates for hundreds of millions of years.
FAQs
Where are these newly discovered neurons located?
They are found in an ancient region of the brainstem.
Could this discovery help ADHD research?
Scientists believe it may lead to more precise future treatments.
