Nerve cells in the brain receive information from many senses at once, raising questions about how the brain determines what is most important to focus on. A recent study by researchers at the University of Oslo, published in Nature Communications, has explored this process.
The team used mice running on a styrofoam wheel inside a virtual maze to observe how their brains respond when focusing on navigation tasks. As the mice navigated toward rewards, scientists monitored their brain activity using microscopes.
The study found that certain brain cells called VIP cells act as an "intelligent amplifier" for important signals. These VIP cells inhibit other cells that usually suppress neural activity, allowing significant information—such as spatial cues needed for navigation—to stand out over irrelevant sensory noise.
"By inhibiting the cells that normally keep activity down, the important signals get through with increased strength," Vervaeke explained.
"What sets this function apart from a passive volume control is that it becomes more like an intelligent amplifier. VIP cells ensure that the important signals you take in about place become clear and strong, while irrelevant background noise is suppressed."
This mechanism helps animals—and potentially humans—focus on relevant information during tasks such as finding their way back to a location, rather than being distracted by unrelated sensory details.
"It appears that the process is governed by how focused you are on the task you are performing," said Vervaeke.
Researchers observed that when this amplifier was active, they could determine exactly where the mouse was in the virtual maze based solely on nerve cell activity because those signals became much clearer.
Previous research led by Nobel laureates May-Britt and Edvard Moser mapped out brain regions responsible for spatial sense and navigation. These areas are known to be among the first affected in dementia patients. Understanding how these amplifier mechanisms work may help explain what happens when memory systems fail due to disease.
"By understanding how these amplifier mechanisms function in a healthy brain, we can better understand what happens when the control systems fail and memories begin to break down," Vervaeke said.
