Early Influences on Brain Architecture

An Interview with Neuroscientist Eric Knudsen

What causes the brain to be less adaptable over time?

The physical and chemical conditions in the brain that exist early in life encourage the building of brain architecture. A young brain is not yet committed to processing information in a particular way. As the brain ages, changes take place that lock-in certain ways of processing information. As time goes on, this makes it difficult for the brain to change to other ways of processing information. Maintaining plasticity—keeping the brain open to change—takes energy and this energy isn’t endless. In addition, there’s a trade-off between plasticity and stability. Brain architecture that remains highly plastic is also less able to preserve what has already been learned. At times, you have to solidify what you’ve learned by locking in a pattern of connectivity. The brain builds on these established patterns. Brain systems need to be stabilized so that high-level systems can depend on them when learning higher functions. Think of it this way: You can’t build a house on shifting sand.

What does your work tell us about enrichment or deprivation, as opposed to appropriate, healthy experience?

We do know a lot about the negative consequences of impoverished environments on the development of brain architecture, and there is much that society can do to reduce neglect and abuse. However, enrichment as it’s usually understood—providing artificially complex experiences beyond the range of what a child would normally encounter in a typical environment—is a tricky subject. There’s little scientific evidence to support the assertion that “enrichment” (like classical music CDs intended to ­increase intelligence, or highly structured classes for toddlers) builds better brains. Most “enrichment” studies, which use animal subjects, simply restore the typically complex conditions under which an animal would learn in its natural environment. So most “enrichment” studies involving animals aren’t really applicable to children living in typical environments. The one caveat is that attention promotes learning, so those activities that help children be more attentive and emotionally engaged (and those two things are linked) will help them to learn better.

What would you say are the broad policy implications or principles that could be derived from your work?

The first very clear implication is that early experience has powerful and lasting influences on how the brain develops. That early malleability is a double-edged sword. It’s a window of opportunity to optimize development, but also a period of vulnerability to harmful or stressful experiences. If children have stressful or impoverished early environments, there will be long-term implications for the building of the brain.

However, though early experience is very important, later experience is also important. You need to have appropriate experiences throughout life to take advantage of the architecture built in childhood, even when that architecture is sturdy and strong. Since the brain develops in a hierarchical fashion, later learning builds on brain architecture that is the result of early experience. If you have good early experiences, grow up in healthy personal and public environments, and build strong “foundational” brain architecture, that makes it more likely that the higher order brain functions and behaviors will develop optimally. So it’s extremely important for policy makers to know that early experience lays the foundation for later learning, and makes later learning much easier and much more efficient. Finally, because later plasticity tends to be more limited, children who may have missed out on positive early experiences—so necessary for sturdy brain architecture development—need to be highly engaged with what they’re learning in order to make changes in their brain architecture. That can be achieved by fostering learning through positive relationships or active experiences—by engaging that child’s attention and emotions. These observations have numerous implications for the nation’s health system and its mental health system, as well as its child care and education systems. At the very least, the scientific research would suggest that these systems need to be examined and restructured to be fully supportive of early childhood development.

The interviewer: Marcy Ray has worked with a number of interdisciplinary research networks. She served as Administrator and Director of Communications for the Research Network on Early Experience and Brain Development, and holds an M.A. in Communication Studies from the University of North Carolina at Chapel Hill.

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