New research from HHMI’s Janelia Research Campus shows that wandering or exploring without a specific goal helps the brain learn. Scientists studied how mouse brains work when they explore, focusing on the visual cortex, the part of the brain that processes what we see. They found that even without tasks, the brain builds an internal map of the world, which makes learning faster when a task is given later.
The study, published in Nature, used a tool called Rastermap to look at the activity of thousands of neurons. Mice explored virtual reality corridors with different visual patterns, like textures on walls. Some patterns led to rewards, while others didn’t. Over weeks, the researchers saw changes in the visual cortex, a sign of neural plasticity, which means the brain’s connections change to help learning and memory. These changes happened even when the mice weren’t trained on a specific task, a process called unsupervised learning, where the brain learns without instructions.
Learning without a teacher
The researchers found that parts of the visual cortex were encoding visual features, like patterns, just from exploration. When a task was added, other parts of the cortex became active. Mice that explored the corridors for weeks learned to connect patterns with rewards faster than mice only trained on the task. This suggests exploring helps the brain prepare for future challenges without needing a teacher.
The study shows the brain uses two types of learning. Unsupervised learning happens during exploration, helping the brain understand the environment. Supervised learning happens during tasks, giving meaning to what’s learned. Both work together when learning something new. This discovery could help explain how brains learn in general, showing that exploration is as important as task-based learning. It also opens new questions about how the visual cortex works with other brain areas to build a full picture of the world.
The research was made possible by a powerful tool called a mesoscope, which recorded up to 90,000 neurons at once, letting scientists see brain activity in detail. The findings suggest that everyday activities, like wandering a city, might help the brain learn and prepare for future tasks, even without a clear goal.