Early learning experiences forever change the brain's structure

Dec 20 2004

Educational Christmas toys can leave a mark on more than just your checkbook - they can also leave a permanent imprint on a child's brain. That's according to a Stanford University School of Medicine study in owls showing that early learning experiences forever change the brain's structure.

Previous work by study leader Eric Knudsen, PhD, professor and chair of neurobiology, showed that young owls could quickly pick up new skills that leave older owls baffled. What's more, once the young owls learn a new skill they can easily pick it back up as an adult.

"This work shows the importance of investing in childhood experiences," said Knudsen, who also holds the Edward C. and Amy H. Sewall Professorship. "Early learning can have long lasting effects on the architecture of the brain."

Knudsen's new work, published Dec. 19 in the online edition of Nature Neuroscience, relies on a well-understood region of an owl's brain. This area creates a spatial map out of the sounds an owl hears, such as the squeaking of a mouse or some rustling in the leaves. The owl then uses that map to know precisely where to hunt for dinner.

In his work, Knudsen and graduate student Brie Linkenhoker put glasses on the owls that shift the world to one side. When the owl first peers through the new specs, a squeaking mouse located off to the side appears to be straight ahead. This confuses the owl and allows its prey to escape.

The hungry owl solves this problem by learning a new auditory map that matches the shifted visual map. It then uses this new map to successfully capture its prey. When Knudsen removes the glasses the owls shift back to the original map of the world. After the human equivalent of many years, those educated owls can once again adjust to the same world-shifting glasses from which they learned as juveniles.

Knudsen, Linkenhoker and graduate student Christina von der Ohe wondered how educated animals held on to their learning. They thought that the neurons might make new connections that remained intact in adult animals. They turned out to be right.

Neurons in the mapping part of the brain form connections with a completely new group of neurons in the brain region that links those noises with the visual world. Adult owls that had learned to work with the glasses as youths had both the normal connections and the shifted connections. Those extra connections meant that the animals could easily relearn, even as adults, to work with the glasses.

Knudsen said different parts of the brain lose the ability to make large-scale changes in connections at different rates. "It's a trade-off between reliability and flexibility," he said. Areas of the brain that need to be reliable in adults, such as the ability to analyze the world or find prey, stop making major structural changes early in life, leaving the adult with a stable map. Other parts of the brain, such as those involved in learning and memory, remain more open to changes throughout life.

This work shows that it's not just the ability to do math or read books that can help a child when they grow up. Those brain regions that help sense and interpret the world are most affected by early childhood experiences. "These have a huge impact on higher functions in later life," Knudsen said.

Toys that beep, crinkle, feel soft, look interesting or require poking and prodding are all part of shaping a child's brain for future work.

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