Researchers at Johns Hopkins University have identified a group of neurons in the brainstem that appears to play a central role in selective spatial attention in mice, helping the animals ignore distractions and respond to the most relevant visual information. The study, published in Nature Communications, found that when the neurons were temporarily switched off, mice became markedly more distractible during an attention task. When the neurons were reactivated, the animals’ ability to focus returned.
The experiments centered on inhibitory neurons in an ancient brain region that the researchers say is shared across vertebrates, including birds, fish and humans. To test the cells’ function, the team used a visual task modeled on those used in human attention research. Mice were rewarded for responding to cues directly in front of them while disregarding competing signals at the side. The animals could perform the task until the brainstem neurons were inactivated, at which point their performance deteriorated. Researchers said additional testing ruled out vision or movement problems, indicating that the impairment was specific to the animals’ ability to compare competing information and select what mattered most.
The findings add to a broader scientific debate over how attention is controlled in the brain. Attention has long been linked primarily to the prefrontal cortex, which is especially developed in humans and other primates. The Johns Hopkins team argues that this view does not fully explain how other animals maintain attention despite lacking a highly developed prefrontal cortex. Lead author Ninad Kothari said the work points to an evolutionarily older brainstem system that supports that ability, while senior author Shreesh Mysore described the neurons as an “attentional selection engine.”
The researchers also drew a connection between the mice’s behavior and symptoms seen in attention-related conditions. Mysore said the distractibility observed after the neurons were silenced resembled a hallmark of ADHD, in which even weak distractions can pull attention away from a task. The team cautioned, however, that the study was conducted in mice and said further work is needed to determine whether the same neurons serve a similar function in humans.
That uncertainty is central to the study’s possible medical significance. The researchers said evidence so far suggests comparable neurons exist in humans, and future studies may examine whether they function differently in people with ADHD or autism. If that proves to be the case, they argue, the discovery could eventually support the development of more targeted treatments for attention-related disorders. For now, the study offers new evidence that a deeply conserved part of the brain may play a larger role in focus than previously understood.